<!DOCTYPE html PUBLIC '-//W3C//DTD HTML 4.01 Transitional//EN' 'http://www.w3.org/TR/html4/loose.dtd'>
<html lang="en" dir="ltr">
<head>
<title>JSON-LD Syntax 1.0</title>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<!--
  === NOTA BENE ===
  For the three scripts below, if your spec resides on dev.w3 you can check them
  out in the same tree and use relative links so that they'll work offline,
  -->


<style>
.diff { font-weight:bold; color:#0a3; }
ol.algorithm.update { margin-left: 2em; }
ol.algorithm.update>li { list-style-type: none; }
ol.algorithm.update>li>span.list-number {
  display:block;
  float: left;
  margin-left: -3.5em;
}
</style>
<style type="text/css">
/*****************************************************************
 * ReSpec CSS
 * Robin Berjon (robin at berjon dot com)
 * v0.05 - 2009-07-31
 *****************************************************************/


/* --- INLINES --- */
em.rfc2119 {
    text-transform:     lowercase;
    font-variant:       small-caps;
    font-style:         normal;
    color:              #900;
}

h1 acronym, h2 acronym, h3 acronym, h4 acronym, h5 acronym, h6 acronym, a acronym,
h1 abbr, h2 abbr, h3 abbr, h4 abbr, h5 abbr, h6 abbr, a abbr {
    border: none;
}

dfn {
    font-weight:    bold;
}

a.internalDFN {
    color:  inherit;
    border-bottom:  1px solid #99c;
    text-decoration:    none;
}

a.externalDFN {
    color:  inherit;
    border-bottom:  1px dotted #ccc;
    text-decoration:    none;
}

a.bibref {
    text-decoration:    none;
}

code {
    color:  #ff4500;
}


/* --- WEB IDL --- */
pre.idl {
    border-top: 1px solid #90b8de;
    border-bottom: 1px solid #90b8de;
    padding:    1em;
    line-height:    120%;
}

pre.idl::before {
    content:    "WebIDL";
    display:    block;
    width:      150px;
    background: #90b8de;
    color:  #fff;
    font-family:    initial;
    padding:    3px;
    font-weight:    bold;
    margin: -1em 0 1em -1em;
}

.idlType {
    color:  #ff4500;
    font-weight:    bold;
    text-decoration:    none;
}

/*.idlModule*/
/*.idlModuleID*/
/*.idlInterface*/
.idlInterfaceID, .idlDictionaryID {
    font-weight:    bold;
    color:  #005a9c;
}

.idlSuperclass {
    font-style: italic;
    color:  #005a9c;
}

/*.idlAttribute*/
.idlAttrType, .idlFieldType, .idlMemberType {
    color:  #005a9c;
}
.idlAttrName, .idlFieldName, .idlMemberName {
    color:  #ff4500;
}
.idlAttrName a, .idlFieldName a, .idlMemberName a {
    color:  #ff4500;
    border-bottom:  1px dotted #ff4500;
    text-decoration: none;
}

/*.idlMethod*/
.idlMethType {
    color:  #005a9c;
}
.idlMethName {
    color:  #ff4500;
}
.idlMethName a {
    color:  #ff4500;
    border-bottom:  1px dotted #ff4500;
    text-decoration: none;
}

/*.idlParam*/
.idlParamType {
    color:  #005a9c;
}
.idlParamName {
    font-style: italic;
}

.extAttr {
    color:  #666;
}

/*.idlConst*/
.idlConstType {
    color:  #005a9c;
}
.idlConstName {
    color:  #ff4500;
}
.idlConstName a {
    color:  #ff4500;
    border-bottom:  1px dotted #ff4500;
    text-decoration: none;
}

/*.idlException*/
.idlExceptionID {
    font-weight:    bold;
    color:  #c00;
}

.idlTypedefID, .idlTypedefType {
    color:  #005a9c;
}

.idlRaises, .idlRaises a.idlType, .idlRaises a.idlType code, .excName a, .excName a code {
    color:  #c00;
    font-weight:    normal;
}

.excName a {
    font-family:    monospace;
}

.idlRaises a.idlType, .excName a.idlType {
    border-bottom:  1px dotted #c00;
}

.excGetSetTrue, .excGetSetFalse, .prmNullTrue, .prmNullFalse, .prmOptTrue, .prmOptFalse {
    width:  45px;
    text-align: center;
}
.excGetSetTrue, .prmNullTrue, .prmOptTrue { color:  #0c0; }
.excGetSetFalse, .prmNullFalse, .prmOptFalse { color:  #c00; }

.idlImplements a {
    font-weight:    bold;
}

dl.attributes, dl.methods, dl.constants, dl.fields, dl.dictionary-members {
    margin-left:    2em;
}

.attributes dt, .methods dt, .constants dt, .fields dt, .dictionary-members dt {
    font-weight:    normal;
}

.attributes dt code, .methods dt code, .constants dt code, .fields dt code, .dictionary-members dt code {
    font-weight:    bold;
    color:  #000;
    font-family:    monospace;
}

.attributes dt code, .fields dt code, .dictionary-members dt code {
    background:  #ffffd2;
}

.attributes dt .idlAttrType code, .fields dt .idlFieldType code, .dictionary-members dt .idlMemberType code {
    color:  #005a9c;
    background:  transparent;
    font-family:    inherit;
    font-weight:    normal;
    font-style: italic;
}

.methods dt code {
    background:  #d9e6f8;
}

.constants dt code {
    background:  #ddffd2;
}

.attributes dd, .methods dd, .constants dd, .fields dd, .dictionary-members dd {
    margin-bottom:  1em;
}

table.parameters, table.exceptions {
    border-spacing: 0;
    border-collapse:    collapse;
    margin: 0.5em 0;
    width:  100%;
}
table.parameters { border-bottom:  1px solid #90b8de; }
table.exceptions { border-bottom:  1px solid #deb890; }

.parameters th, .exceptions th {
    color:  #fff;
    padding:    3px 5px;
    text-align: left;
    font-family:    initial;
    font-weight:    normal;
    text-shadow:    #666 1px 1px 0;
}
.parameters th { background: #90b8de; }
.exceptions th { background: #deb890; }

.parameters td, .exceptions td {
    padding:    3px 10px;
    border-top: 1px solid #ddd;
    vertical-align: top;
}

.parameters tr:first-child td, .exceptions tr:first-child td {
    border-top: none;
}

.parameters td.prmName, .exceptions td.excName, .exceptions td.excCodeName {
    width:  100px;
}

.parameters td.prmType {
    width:  120px;
}

table.exceptions table {
    border-spacing: 0;
    border-collapse:    collapse;
    width:  100%;
}

/* --- TOC --- */
.toc a {
    text-decoration:    none;
}

a .secno {
    color:  #000;
}

/* --- TABLE --- */
table.simple {
    border-spacing: 0;
    border-collapse:    collapse;
    border-bottom:  3px solid #005a9c;
}

.simple th {
    background: #005a9c;
    color:  #fff;
    padding:    3px 5px;
    text-align: left;
}

.simple th[scope="row"] {
    background: inherit;
    color:  inherit;
    border-top: 1px solid #ddd;
}

.simple td {
    padding:    3px 10px;
    border-top: 1px solid #ddd;
}

.simple tr:nth-child(even) {
    background: #f0f6ff;
}

/* --- DL --- */
.section dd > p:first-child {
    margin-top: 0;
}

.section dd > p:last-child {
    margin-bottom: 0;
}

.section dd {
    margin-bottom:  1em;
}

.section dl.attrs dd, .section dl.eldef dd {
    margin-bottom:  0;
}

/* --- EXAMPLES --- */
pre.example {
    border-top: 1px solid #ff4500;
    border-bottom: 1px solid #ff4500;
    padding:    1em;
    margin-top: 1em;
}

pre.example::before {
    content:    "Example";
    display:    block;
    width:      150px;
    background: #ff4500;
    color:  #fff;
    font-family:    initial;
    padding:    3px;
    font-weight:    bold;
    margin: -1em 0 1em -1em;
}

/* --- EDITORIAL NOTES --- */
.issue {
    padding:    1em;
    margin: 1em 0em 0em;
    border: 1px solid #f00;
    background: #ffc;
}

.issue::before {
    content:    "Issue";
    display:    block;
    width:  150px;
    margin: -1.5em 0 0.5em 0;
    font-weight:    bold;
    border: 1px solid #f00;
    background: #fff;
    padding:    3px 1em;
}

.note {
    margin: 1em 0em 0em;
    padding:    1em;
    border: 2px solid #cff6d9;
    background: #e2fff0;
}

.note::before {
    content:    "Note";
    display:    block;
    width:  150px;
    margin: -1.5em 0 0.5em 0;
    font-weight:    bold;
    border: 1px solid #cff6d9;
    background: #fff;
    padding:    3px 1em;
}

/* --- Best Practices --- */
div.practice {
    border: solid #bebebe 1px;
    margin: 2em 1em 1em 2em;
}

span.practicelab {
    margin: 1.5em 0.5em 1em 1em;
    font-weight: bold;
    font-style: italic;
}

span.practicelab   { background: #dfffff; }

span.practicelab {
    position: relative;
    padding: 0 0.5em;
    top: -1.5em;
}

p.practicedesc {
    margin: 1.5em 0.5em 1em 1em;
}

@media screen {
    p.practicedesc {
        position: relative;
        top: -2em;
        padding: 0;
        margin: 1.5em 0.5em -1em 1em;
    }
}

/* --- SYNTAX HIGHLIGHTING --- */
pre.sh_sourceCode {
  background-color: white;
  color: black;
  font-style: normal;
  font-weight: normal;
}

pre.sh_sourceCode .sh_keyword { color: #005a9c; font-weight: bold; }           /* language keywords */
pre.sh_sourceCode .sh_type { color: #666; }                            /* basic types */
pre.sh_sourceCode .sh_usertype { color: teal; }                             /* user defined types */
pre.sh_sourceCode .sh_string { color: red; font-family: monospace; }        /* strings and chars */
pre.sh_sourceCode .sh_regexp { color: orange; font-family: monospace; }     /* regular expressions */
pre.sh_sourceCode .sh_specialchar { color: 	#ffc0cb; font-family: monospace; }  /* e.g., \n, \t, \\ */
pre.sh_sourceCode .sh_comment { color: #A52A2A; font-style: italic; }         /* comments */
pre.sh_sourceCode .sh_number { color: purple; }                             /* literal numbers */
pre.sh_sourceCode .sh_preproc { color: #00008B; font-weight: bold; }       /* e.g., #include, import */
pre.sh_sourceCode .sh_symbol { color: blue; }                            /* e.g., *, + */
pre.sh_sourceCode .sh_function { color: black; font-weight: bold; }         /* function calls and declarations */
pre.sh_sourceCode .sh_cbracket { color: red; }                              /* block brackets (e.g., {, }) */
pre.sh_sourceCode .sh_todo { font-weight: bold; background-color: #00FFFF; }   /* TODO and FIXME */

/* Predefined variables and functions (for instance glsl) */
pre.sh_sourceCode .sh_predef_var { color: #00008B; }
pre.sh_sourceCode .sh_predef_func { color: #00008B; font-weight: bold; }

/* for OOP */
pre.sh_sourceCode .sh_classname { color: teal; }

/* line numbers (not yet implemented) */
pre.sh_sourceCode .sh_linenum { display: none; }

/* Internet related */
pre.sh_sourceCode .sh_url { color: blue; text-decoration: underline; font-family: monospace; }

/* for ChangeLog and Log files */
pre.sh_sourceCode .sh_date { color: blue; font-weight: bold; }
pre.sh_sourceCode .sh_time, pre.sh_sourceCode .sh_file { color: #00008B; font-weight: bold; }
pre.sh_sourceCode .sh_ip, pre.sh_sourceCode .sh_name { color: #006400; }

/* for Prolog, Perl... */
pre.sh_sourceCode .sh_variable { color: #006400; }

/* for LaTeX */
pre.sh_sourceCode .sh_italics { color: #006400; font-style: italic; }
pre.sh_sourceCode .sh_bold { color: #006400; font-weight: bold; }
pre.sh_sourceCode .sh_underline { color: #006400; text-decoration: underline; }
pre.sh_sourceCode .sh_fixed { color: green; font-family: monospace; }
pre.sh_sourceCode .sh_argument { color: #006400; }
pre.sh_sourceCode .sh_optionalargument { color: purple; }
pre.sh_sourceCode .sh_math { color: orange; }
pre.sh_sourceCode .sh_bibtex { color: blue; }

/* for diffs */
pre.sh_sourceCode .sh_oldfile { color: orange; }
pre.sh_sourceCode .sh_newfile { color: #006400; }
pre.sh_sourceCode .sh_difflines { color: blue; }

/* for css */
pre.sh_sourceCode .sh_selector { color: purple; }
pre.sh_sourceCode .sh_property { color: blue; }
pre.sh_sourceCode .sh_value { color: #006400; font-style: italic; }

/* other */
pre.sh_sourceCode .sh_section { color: black; font-weight: bold; }
pre.sh_sourceCode .sh_paren { color: red; }
pre.sh_sourceCode .sh_attribute { color: #006400; }

</style><style type="text/css">ol.algorithm { counter-reset:numsection; list-style-type: none; }
ol.algorithm li { margin: 0.5em 0; }
ol.algorithm li:before { font-weight: bold; counter-increment: numsection; content: counters(numsection, ".") ") "; }

</style><link charset="utf-8" type="text/css" rel="stylesheet" href="http://www.w3.org/StyleSheets/TR/w3c-unofficial"><style type='text/css'>
.diff-old-a {
  font-size: smaller;
  color: red;
}

.diff-new { background-color: yellow; }
.diff-chg { background-color: lime; }
.diff-new:before,
.diff-new:after
    { content: "\2191" }
.diff-chg:before, .diff-chg:after
    { content: "\2195" }
.diff-old { text-decoration: line-through; background-color: #FBB; }
.diff-old:before,
.diff-old:after
    { content: "\2193" }
:focus { border: thin red solid}
</style>
</head>


<body style="display: inherit;">
<div class="head">
<p>
</p>
<h1 class="title" id="title">
JSON-LD
Syntax
1.0
</h1>
<h2 id="subtitle">
A
Context-based
JSON
Serialization
for
Linking
Data
</h2>
<h2 id="unofficial-draft-18-march-2012">
Unofficial
Draft
<del class="diff-old">22
January
</del>
<ins class="diff-chg">18
March
</ins>
2012
</h2>
<dl>
<dt>
Editors:
</dt>
<dd>
<a href="http://manu.sporny.org/">
Manu
Sporny
</a>,
<a href="http://digitalbazaar.com/">
Digital
Bazaar
</a>
</dd>
<dd>
<a href="http://greggkellogg.net/">
Gregg
Kellogg
</a>,
<a href="http://kellogg-assoc.com/">
Kellogg
Associates
</a>
</dd>
<dt>
Authors:
</dt>
<dd>
<a href="http://digitalbazaar.com/">
Manu
Sporny
</a>,
<a href="http://digitalbazaar.com/">
Digital
Bazaar
</a>
</dd>
<dd>
<a href="http://digitalbazaar.com/">
Dave
Longley
</a>,
<a href="http://digitalbazaar.com/">
Digital
Bazaar
</a>
</dd>
<dd>
<a href="http://greggkellogg.net/">
Gregg
Kellogg
</a>,
<a href="http://kellogg-assoc.com/">
Kellogg
Associates
</a>
</dd>
<dd>
<a href="http://www.markus-lanthaler.com/">
Markus
Lanthaler
</a>,
<a href="http://www.tugraz.at/">
Graz
University
of
Technology
</a>
</dd>
<dd>
<a href="http://webbackplane.com/">
Mark
Birbeck
</a>,
<a href="http://webbackplane.com/">
Backplane
Ltd.
</a>
</dd>
</dl>
<p>
This
document
is
also
available
in
this
non-normative
format:
<a href="diff-20120122.html">
diff
to
previous
version
</a>.
</p>
<p class="copyright">
This
document
is
licensed
under
a
<a class="subfoot" href="http://creativecommons.org/licenses/by/3.0/" rel="license">
Creative
Commons
Attribution
3.0
License
</a>.
</p>
<hr>
</div>
<div class="introductory section" id="abstract">
<h2>
Abstract
</h2>
<p>
JSON
[
<cite>
<a href="#bib-RFC4627" rel="biblioentry" class="bibref">
RFC4627
</a>
</cite>
]
has
proven
to
be
a
highly
useful
object
serialization
and
messaging
format.
In
an
attempt
to
harmonize
the
representation
of
<a href="#dfn-linked_data" title="linked_data" class="tref internalDFN">
Linked
Data
</a>
in
JSON,
this
specification
outlines
a
common
JSON
representation
format
for
expressing
directed
graphs;
mixing
both
Linked
Data
and
non-Linked
Data
in
a
single
document.
</p>
</div>
<div id="sotd" class="introductory section">
<h2>
Status
of
This
Document
</h2>
<p>
This
document
is
merely
a
public
working
draft
of
a
potential
specification.
It
has
no
official
standing
of
any
kind
and
does
not
represent
the
support
or
consensus
of
any
standards
organisation.
</p>
<p>
This
document
is
an
experimental
work
in
progress.
</p>
</div>
<div class="section" id="toc">
<h2 class="introductory">
Table
of
Contents
</h2>
<ul class="toc">
<li class="tocline">
<a class="tocxref" href="#introduction">
<span class="secno">
1.
</span>
Introduction
</a>
<ul class="toc">
<li class="tocline">
<a class="tocxref" href="#how-to-read-this-document">
<span class="secno">
1.1
</span>
How
to
Read
this
Document
</a>
</li>
<li class="tocline">
<a class="tocxref" href="#syntax-tokens-and-keywords">
<span class="secno">
1.2
</span>
Syntax
Tokens
and
Keywords
</a>
</li>
<li class="tocline">
<a class="tocxref" href="#contributing">
<span class="secno">
1.3
</span>
Contributing
</a>
</li>
</ul>
</li>
<li class="tocline">
<a class="tocxref" href="#design">
<span class="secno">
2.
</span>
Design
</a>
<ul class="toc">
<li class="tocline">
<a class="tocxref" href="#goals-and-rationale">
<span class="secno">
2.1
</span>
Goals
and
Rationale
</a>
</li>
<li class="tocline">
<a class="tocxref" href="#linking-data">
<span class="secno">
2.2
</span>
Linking
Data
</a>
<ul class="toc">
<li class="tocline">
<a class="tocxref" href="#the-context">
<span class="secno">
2.2.1
</span>
The
Context
</a>
</li>
<li class="tocline">
<a class="tocxref" href="#from-json-to-json-ld">
<span class="secno">
2.2.2
</span>
From
JSON
to
JSON-LD
</a>
</li>
</ul>
</li>
</ul>
</li>
<li class="tocline">
<a class="tocxref" href="#basic-concepts">
<span class="secno">
3.
</span>
Basic
Concepts
</a>
<ul class="toc">
<li class="tocline">
<a class="tocxref" href="#iris">
<span class="secno">
3.1
</span>
IRIs
</a>
</li>
<li class="tocline">
<a class="tocxref" href="#identifying-the-subject">
<span class="secno">
3.2
</span>
Identifying
the
Subject
</a>
</li>
<li class="tocline">
<a class="tocxref" href="#specifying-the-type">
<span class="secno">
3.3
</span>
Specifying
the
Type
</a>
</li>
<li class="tocline">
<a class="tocxref" href="#strings">
<span class="secno">
3.4
</span>
Strings
</a>
</li>
<li class="tocline">
<a class="tocxref" href="#string-internationalization">
<span class="secno">
3.5
</span>
String
Internationalization
</a>
</li>
<li class="tocline">
<a class="tocxref" href="#typed-values">
<span class="secno">
3.6
</span>
Typed
Values
</a>
</li>
<li class="tocline">
<a class="tocxref" href="#multiple-objects-for-a-single-property">
<span class="secno">
3.7
</span>
Multiple
Objects
for
a
Single
Property
</a>
</li>
<li class="tocline">
<a class="tocxref" href="#multiple-values-for-a-single-property">
<span class="secno">
3.8
</span>
Multiple
Values
for
a
Single
Property
</a>
</li>
<li class="tocline">
<a class="tocxref" href="#lists">
<span class="secno">
3.9
</span>
Lists
</a>
</li>
</ul>
</li>
<li class="tocline">
<a class="tocxref" href="#advanced-concepts">
<span class="secno">
4.
</span>
Advanced
Concepts
</a>
<ul class="toc">
<li class="tocline">
<a class="tocxref" href="#compact-iris">
<span class="secno">
4.1
</span>
<del class="diff-old">Prefixes
</del>
<ins class="diff-chg">Compact
IRIs
</ins>
</a>
</li>
<li class="tocline">
<a class="tocxref" href="#external-contexts">
<span class="secno">
4.2
</span>
External
Contexts
</a>
</li>
<li class="tocline">
<a class="tocxref" href="#referencing-contexts-from-json-documents">
<span class="secno">
4.3
</span>
<ins class="diff-new">Referencing
Contexts
from
JSON
Documents
</ins></a></li><li class="tocline"><a class="tocxref" href="#default-language"><span class="secno"><ins class="diff-new">
4.4
</ins></span>
Default
Language
</a>
</li>
<li class="tocline">
<a class="tocxref" href="#expanded-term-definition">
<span class="secno">
<del class="diff-old">4.4
</del>
<ins class="diff-chg">4.5
</ins>
</span>
Expanded
Term
Definition
</a>
</li>
<li class="tocline">
<a class="tocxref" href="#automatic-typing">
<span class="secno">
<del class="diff-old">4.5
</del>
<ins class="diff-chg">4.6
</ins>
</span>
Automatic
Typing
</a>
</li>
<li class="tocline">
<a class="tocxref" href="#type-coercion">
<span class="secno">
<del class="diff-old">4.6
</del>
<ins class="diff-chg">4.7
</ins>
</span>
Type
Coercion
</a>
</li>
<li class="tocline">
<a class="tocxref" href="#iri-expansion-within-a-context">
<span class="secno">
<del class="diff-old">4.7
</del>
<ins class="diff-chg">4.8
</ins>
</span>
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
Expansion
Within
a
Context
</a>
</li>
<li class="tocline">
<a class="tocxref" href="#embedding">
<span class="secno">
<del class="diff-old">4.8
</del>
<ins class="diff-chg">4.9
</ins>
</span>
Embedding
</a>
</li>
<li class="tocline">
<a class="tocxref" href="#identifying-unlabeled-nodes">
<span class="secno">
<del class="diff-old">4.9
</del>
<ins class="diff-chg">4.10
</ins>
</span>
Identifying
Unlabeled
Nodes
</a>
</li>
<li class="tocline">
<a class="tocxref" href="#aliasing-keywords">
<span class="secno">
<del class="diff-old">4.10
</del>
<ins class="diff-chg">4.11
</ins>
</span>
Aliasing
Keywords
</a>
</li>
<li class="tocline">
<a class="tocxref" href="#expansion">
<span class="secno">
<ins class="diff-new">4.12
</ins></span><ins class="diff-new">
Expansion
</ins></a></li><li class="tocline"><a class="tocxref" href="#compaction"><span class="secno"><ins class="diff-new">
4.13
</ins></span><ins class="diff-new">
Compaction
</ins></a></li><li class="tocline"><a class="tocxref" href="#framing"><span class="secno"><ins class="diff-new">
4.14
</ins></span><ins class="diff-new">
Framing
</ins></a></li><li class="tocline"><a class="tocxref" href="#normalization"><span class="secno"><ins class="diff-new">
4.15
</ins></span><ins class="diff-new">
Normalization
</ins></a></li>
</ul>
</li>
<li class="tocline">
<a class="tocxref" href="#markup-examples">
<span class="secno">
A.
</span>
Markup
Examples
</a>
<ul class="toc">
<li class="tocline">
<a class="tocxref" href="#turtle">
<span class="secno">
A.1
</span>
Turtle
</a>
<ul class="toc">
<li class="tocline">
<a class="tocxref" href="#prefix-definitions">
<span class="secno">
A.1.1
</span>
Prefix
definitions
</a>
</li>
<li class="tocline">
<a class="tocxref" href="#embedding-1">
<span class="secno">
A.1.2
</span>
Embedding
</a>
</li>
<li class="tocline">
<a class="tocxref" href="#lists-1">
<span class="secno">
A.1.3
</span>
Lists
</a>
</li>
</ul>
</li>
<li class="tocline">
<a class="tocxref" href="#rdfa">
<span class="secno">
A.2
</span>
RDFa
</a>
</li>
<li class="tocline">
<a class="tocxref" href="#microformats">
<span class="secno">
A.3
</span>
Microformats
</a>
</li>
<li class="tocline">
<a class="tocxref" href="#microdata">
<span class="secno">
A.4
</span>
Microdata
</a>
</li>
</ul>
</li>
<li class="tocline">
<a class="tocxref" href="#linked-data">
<span class="secno">
B.
</span>
Linked
Data
</a>
</li>
<li class="tocline">
<a class="tocxref" href="#mashing-up-vocabularies">
<span class="secno">
C.
</span>
Mashing
Up
Vocabularies
</a>
</li>
<li class="tocline">
<a class="tocxref" href="#iana-considerations">
<span class="secno">
D.
</span>
IANA
Considerations
</a>
</li>
<li class="tocline">
<a class="tocxref" href="#acknowledgements">
<span class="secno">
E.
</span>
Acknowledgements
</a>
</li>
<li class="tocline">
<a class="tocxref" href="#references">
<span class="secno">
F.
</span>
References
</a>
<ul class="toc">
<li class="tocline">
<a class="tocxref" href="#normative-references">
<span class="secno">
F.1
</span>
Normative
references
</a>
</li>
<li class="tocline">
<a class="tocxref" href="#informative-references">
<span class="secno">
F.2
</span>
Informative
references
</a>
</li>
</ul>
</li>
</ul>
</div>
<div id="introduction" class="informative section">
<h2>
<span class="secno">
1.
</span>
Introduction
</h2>
<p>
<em>
This
section
is
non-normative.
</em>
</p>
<p>
JSON,
as
specified
in
[
<cite>
<a href="#bib-RFC4627" rel="biblioentry" class="bibref">
RFC4627
</a>
</cite>
],
is
a
simple
language
for
representing
data
on
the
Web.
<a href="#dfn-linked_data" title="linked_data" class="tref internalDFN">
Linked
Data
</a>
is
a
technique
for
creating
a
graph
of
interlinked
data
across
different
documents
or
Web
sites.
Data
entities
are
described
using
<a href="#dfn-iri" title="iri" class="tref internalDFN">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
s,
which
are
typically
dereferencable
and
thus
may
be
used
to
find
more
information
about
an
entity,
creating
a
<del class="diff-old">&quot;Web
</del>
<ins class="diff-chg">"Web
</ins>
of
<del class="diff-old">Knowledge&quot;.
</del>
<ins class="diff-chg">Knowledge".
</ins>
JSON-LD
is
intended
to
be
a
simple
publishing
method
for
expressing
not
only
Linked
Data
in
JSON,
but
also
for
adding
semantics
to
existing
JSON.
</p>
<p>
JSON-LD
is
designed
as
a
lightweight
syntax
that
can
be
used
to
express
<a href="#dfn-linked_data" title="linked_data" class="tref internalDFN">
Linked
Data
</a>.
It
is
primarily
intended
to
be
a
way
to
use
Linked
Data
in
Javascript
and
other
Web-based
programming
environments.
It
is
also
useful
when
building
interoperable
Web
services
and
when
storing
Linked
Data
in
JSON-based
document
storage
engines.
It
is
practical
and
designed
to
be
as
simple
as
possible,
utilizing
the
large
number
of
JSON
parsers
and
libraries
available
today.
</p>
<p>
The
syntax
does
not
necessarily
require
applications
to
change
their
JSON,
but
allows
one
to
easily
add
meaning
by
simply
adding
or
referencing
a
context.
The
syntax
is
designed
to
not
disturb
already
deployed
systems
running
on
JSON,
but
provide
a
smooth
upgrade
path
from
JSON
to
JSON-LD
with
added
semantics.
Finally,
the
format
is
intended
to
be
easy
to
parse,
efficient
to
generate,
and
only
requires
a
very
small
memory
footprint
in
order
to
operate.
</p>
<div class="section" id="how-to-read-this-document">
<h3>
<span class="secno">
1.1
</span>
How
to
Read
this
Document
</h3>
<p>
This
document
is
a
detailed
specification
for
a
serialization
of
Linked
Data
in
JSON.
The
document
is
primarily
intended
for
the
following
audiences:
</p>
<ul>
<li>
Software
developers
that
want
to
encode
Linked
Data
in
a
way
that
is
cross-language
compatible
via
JSON.
</li>
<li>
Software
developers
that
want
to
understand
the
design
decisions
and
language
syntax
for
JSON-LD.
</li>
<li>
Software
developers
that
want
to
implement
processors
and
APIs
for
JSON-LD.
</li>
</ul>
<p>
This
specification
does
not
describe
the
programming
interfaces
for
the
JSON-LD
Syntax.
The
specification
that
describes
the
programming
interfaces
for
JSON-LD
documents
is
the
JSON-LD
Application
Programming
Interface
[
<cite>
<a href="#bib-JSON-LD-API" rel="biblioentry" class="bibref">
JSON-LD-API
</a>
</cite>
].
</p>
<p>
To
understand
the
basics
in
this
specification
you
must
first
be
familiar
with
JSON,
which
is
detailed
in
[
<cite>
<a href="#bib-RFC4627" rel="biblioentry" class="bibref">
RFC4627
</a>
</cite>
].
To
understand
the
API
and
how
it
is
intended
to
operate
in
a
programming
environment,
it
is
useful
to
have
working
knowledge
of
the
JavaScript
programming
language
[
<cite>
<a href="#bib-ECMA-262" rel="biblioentry" class="bibref">
ECMA-262
</a>
</cite>
]
and
WebIDL
[
<cite>
<a href="#bib-WEBIDL" rel="biblioentry" class="bibref">
WEBIDL
</a>
</cite>
].
</p>
<p>
JSON
[
<cite>
<a href="#bib-RFC4627" rel="biblioentry" class="bibref">
RFC4627
</a>
</cite>
]
defines
several
terms
which
are
used
throughout
this
document:
</p>
<dl>
<dt>
<dfn id="dfn-json_object" title="json_object">
JSON
Object
</dfn>
</dt>
<dd>
An
object
structure
is
represented
as
a
pair
of
curly
brackets
surrounding
zero
or
more
name/value
pairs
(or
members).
A
name
is
a
<a href="#dfn-string" title="string" class="tref internalDFN">
string
</a>.
A
single
colon
comes
after
each
name,
separating
the
name
from
the
value.
A
single
comma
separates
a
value
from
a
following
name.
The
names
within
an
object
<em title="should" class="rfc2119">
should
</em>
be
unique.
</dd>
<dt>
<dfn id="dfn-array" title="array">
array
</dfn>
</dt>
<dd>
An
array
is
an
ordered
collection
of
values.
An
array
structure
is
represented
as
square
brackets
surrounding
zero
or
more
values
(or
elements).
Elements
are
separated
by
commas.
Within
JSON-LD,
array
order
is
not
preserved
by
default,
unless
specific
markup
is
provided
(see
<a href="#lists">
Lists
</a>
).
This
is
because
the
basic
data
model
of
JSON-LD
is
a
<a href="#dfn-linked_data_graph" title="linked_data_graph" class="tref internalDFN">
linked
data
graph
</a>,
which
is
inherently
unordered.
</dd>
<dt>
<dfn id="dfn-string" title="string">
string
</dfn>
</dt>
<dd>
A
string
is
a
sequence
of
zero
or
more
Unicode
characters,
wrapped
in
double
quotes,
using
backslash
escapes.
A
character
is
represented
as
a
single
character
string.
</dd>
<dt>
<dfn id="dfn-number" title="number">
number
</dfn>
</dt>
<dd>
A
number
is
is
similar
to
that
used
in
most
programming
languages,
except
that
the
octal
and
hexadecimal
formats
are
not
used
and
that
leading
zeros
are
not
allowed.
</dd>
<dt>
<dfn id="dfn-true" title="true">
true
</dfn>
and
<dfn id="dfn-false" title="false">
false
</dfn>
</dt>
<dd>
Values
that
are
used
to
express
one
of
two
possible
boolean
states.
</dd>
<dt>
<dfn id="dfn-null" title="null">
null
</dfn>
</dt>
<dd>
The
use
of
the
<em>
null
</em>
value
is
undefined
within
JSON-LD.
</dd>
</dl>
<p>
</p>
</div>
<div class="section" id="syntax-tokens-and-keywords">
<h3>
<span class="secno">
1.2
</span>
Syntax
Tokens
and
Keywords
</h3>
<p>
JSON-LD
specifies
a
number
of
syntax
tokens
and
keywords
that
are
using
in
all
algorithms
described
in
this
section:
</p>
<dl>
<dt>
<code>
@context
</code>
</dt>
<dd>
Used
to
define
the
short-hand
names
that
are
used
throughout
a
JSON-LD
document.
These
short-hand
names
are
called
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>
s
and
help
developers
express
specific
identifiers
in
a
compact
manner.
The
<code>
@context
</code>
keyword
is
described
in
detail
in
the
section
titled
<a href="#the-context">
The
Context
</a>.
</dd>
<dt>
<code>
@id
</code>
</dt>
<dd>
Used
to
uniquely
identify
things
that
are
being
described
in
the
document.
This
keyword
is
described
in
the
section
titled
<a href="#identifying-the-subject">
Identifying
the
Subject
</a>.
</dd>
<dt>
<code>
@value
</code>
</dt>
<dd>
Used
to
specify
the
data
that
is
associated
with
a
particular
<a href="#dfn-property" title="property" class="tref internalDFN">
property
</a>
in
the
graph.
This
keyword
is
described
in
the
sections
titled
<a href="#string-internationalization">
String
Internationalization
</a>
and
<a href="#typed-values">
Typed
Values
</a>.
</dd>
<dt>
<code>
@language
</code>
</dt>
<dd>
Used
to
specify
the
native
language
for
a
particular
value.
This
keyword
is
described
in
the
section
titled
<a href="#string-internationalization">
String
Internationalization
</a>.
</dd>
<dt>
<code>
@type
</code>
</dt>
<dd>
Used
to
set
the
data
type
of
a
<a href="#dfn-subject" title="subject" class="tref internalDFN">
subject
</a>
or
<a href="#dfn-typed_value" title="typed_value" class="tref internalDFN">
typed
value
</a>.
This
keyword
is
described
in
the
section
titled
<a href="#typed-values">
Typed
Values
</a>.
</dd>
<dt>
<code>
<ins class="diff-new">@container
</ins></code></dt><dd><ins class="diff-new">
Used
to
set
the
container
of
a
particular
value.
This
keyword
is
described
in
the
section
titled
</ins><a href="#lists"><ins class="diff-new">
Lists
</ins></a>.</dd><dt><code>
@list
</code>
</dt>
<dd>
Used
to
express
an
ordered
set
of
data.
This
keyword
is
described
in
the
section
titled
<a href="#lists">
Lists
</a>.
</dd>
<dt>
<code>:
</code>
</dt>
<dd>
The
separator
for
JSON
keys
and
values
that
use
<del class="diff-old">the
prefix
mechanism.
</del>
<a href="#dfn-compact_iri" title="compact_iri" class="tref internalDFN">
<ins class="diff-chg">compact
IRIs
</ins></a>.
</dd>
</dl>
<p>
<ins class="diff-new">For
the
avoidance
of
doubt,
all
keys,
keywords
and
values
in
JSON-LD
are
case-sensitive.
</ins></p>
</div>
<div class="section" id="contributing">
<h3>
<span class="secno">
1.3
</span>
Contributing
</h3>
<p>
There
are
a
number
of
ways
that
one
may
participate
in
the
development
of
this
specification:
</p>
<ul>
<li>
Technical
discussion
typically
occurs
on
the
public
mailing
list:
<a href="http://lists.w3.org/Archives/Public/public-linked-json/">
public-linked-json@w3.org
</a>
</li>
<li>
<a href="http://json-ld.org/minutes/">
Public
teleconferences
</a>
are
held
every
week
on
Tuesdays
at
1500
UTC.
</li>
<li>
Specification
bugs
and
issues
should
be
reported
in
the
<a href="https://github.com/json-ld/json-ld.org/issues">
issue
tracker
</a>.
</li>
<li>
<a href="https://github.com/json-ld/json-ld.org/tree/main/spec">
Source
code
</a>
for
the
specification
can
be
found
on
Github.
</li>
<li>
The
<a href="http://webchat.freenode.net/?channels=#json-ld">
#json-ld
</a>
IRC
channel
is
available
for
real-time
discussion
on
irc.freenode.net.
</li>
</ul>
</div>
</div>
<div id="design" class="informative section">
<h2>
<span class="secno">
2.
</span>
Design
</h2>
<p>
<em>
This
section
is
non-normative.
</em>
</p>
<p>
The
following
section
outlines
the
design
goals
and
rationale
behind
the
JSON-LD
markup
language.
</p>
<div class="section" id="goals-and-rationale">
<h3>
<span class="secno">
2.1
</span>
Goals
and
Rationale
</h3>
<p>
A
number
of
design
considerations
were
explored
during
the
creation
of
this
markup
language:
</p>
<dl>
<dt>
Simplicity
</dt>
<dd>
Developers
need
only
know
JSON
and
two
keywords
(
<code>
@context
</code>
and
<code>
@id
</code>
)
to
use
the
basic
functionality
in
JSON-LD.
No
extra
processors
or
software
libraries
are
necessary
to
use
JSON-LD
in
its
most
basic
form.
The
language
attempts
to
ensure
that
developers
have
an
easy
learning
curve.
</dd>
<dt>
Compatibility
</dt>
<dd>
The
JSON-LD
markup
must
be
100%
compatible
with
JSON.
This
ensures
that
all
of
the
standard
JSON
libraries
work
seamlessly
with
JSON-LD
documents.
</dd>
<dt>
Expressiveness
</dt>
<dd>
The
syntax
must
be
able
to
express
directed
graphs,
which
have
been
proven
to
be
able
to
simply
express
almost
every
real
world
data
model.
</dd>
<dt>
Terseness
</dt>
<dd>
The
JSON-LD
syntax
must
be
very
terse
and
human
readable,
requiring
as
little
effort
as
possible
from
the
developer.
</dd>
<dt>
Zero
Edits,
most
of
the
time
</dt>
<dd>
JSON-LD
provides
a
mechanism
that
allows
developers
to
specify
<a href="#dfn-context" title="context" class="tref internalDFN">
context
</a>
in
a
way
that
is
out-of-band.
This
allows
organizations
that
have
already
deployed
large
JSON-based
infrastructure
to
add
meaning
to
their
JSON
documents
in
a
way
that
is
not
disruptive
to
their
day-to-day
operations
and
is
transparent
to
their
current
customers.
At
times,
mapping
JSON
to
a
graph
representation
can
become
difficult.
In
these
instances,
rather
than
having
JSON-LD
support
esoteric
markup,
we
chose
not
to
support
the
use
case
and
support
a
simplified
syntax
instead.
So,
while
Zero
Edits
is
a
goal,
it
is
not
always
possible
without
adding
great
complexity
to
the
language.
</dd>
<dt>
One-pass
Processing
</dt>
<dd>
JSON-LD
supports
one-pass
processing,
which
results
in
a
very
small
memory
footprint
when
processing
documents.
For
example,
to
expand
a
JSON-LD
document
from
a
compacted
form,
only
one
pass
is
required
over
the
data.
</dd>
</dl>
</div>
<div class="section" id="linking-data">
<h3>
<span class="secno">
2.2
</span>
Linking
Data
</h3>
<p>
An
Internationalized
Resource
Identifier
(
<dfn id="dfn-iri" title="iri">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</dfn>
),
as
described
in
[
<cite>
<a href="#bib-RFC3987" rel="biblioentry" class="bibref">
RFC3987
</a>
</cite>
],
is
a
mechanism
for
representing
unique
identifiers
on
the
web.
In
<a href="#dfn-linked_data" title="linked_data" class="tref internalDFN">
Linked
Data
</a>,
an
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
is
commonly
used
for
expressing
a
<a href="#dfn-subject" title="subject" class="tref internalDFN">
subject
</a>,
a
<a href="#dfn-property" title="property" class="tref internalDFN">
property
</a>
or
an
<a href="#dfn-object" title="object" class="tref internalDFN">
object
</a>.
</p>
<p>
JSON-LD
defines
a
mechanism
to
map
JSON
terms,
i.e.,
keys
and
values,
to
IRIs.
This
does
not
mean
that
JSON-LD
requires
every
key
or
value
to
be
an
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>,
but
rather
ensures
that
keys
and
values
can
be
mapped
to
IRIs
if
the
developer
desires
to
transform
their
data
into
<a href="#dfn-linked_data" title="linked_data" class="tref internalDFN">
Linked
Data
</a>.
There
are
a
few
techniques
that
can
ensure
that
developers
will
generate
good
Linked
Data
for
the
Web.
JSON-LD
formalizes
those
techniques.
</p>
<p>
We
will
be
using
the
following
JSON
markup
as
the
example
for
the
rest
of
this
section:
</p>
<del class="diff-old">{
  &quot;name&quot;: &quot;Manu Sporny&quot;,
  &quot;homepage&quot;: &quot;http://manu.sporny.org/&quot;,
  &quot;depiction&quot;: &quot;http://twitter.com/account/profile_image/manusporny&quot;
</del>
<pre class="example">{
<ins class="diff-chg">  "name": "Manu Sporny",
  "homepage": "http://manu.sporny.org/",
  "depiction": "http://twitter.com/account/profile_image/manusporny"
</ins>
}
</pre>
<div class="section" id="the-context">
<h4>
<span class="secno">
2.2.1
</span>
The
Context
</h4>
<p>
In
JSON-LD,
a
<dfn id="dfn-context" title="context">
context
</dfn>
is
used
to
map
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>
s,
i.e.,
keys
with
associated
values
in
an
JSON
document,
to
<a href="#dfn-iri" title="iri" class="tref internalDFN">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
s.
A
<dfn id="dfn-term" title="term">
term
</dfn>
is
a
short
word
that
<em title="may" class="rfc2119">
may
</em>
be
expanded
to
an
<a href="#dfn-iri" title="iri" class="tref internalDFN">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>.
A
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>
<em title="must" class="rfc2119">
must
</em>
have
the
lexical
form
of
<cite>
<a href="http://www.w3.org/TR/2009/REC-xml-names-20091208/#NT-NCName">
NCName
</a>
</cite>
(see
[
<cite>
<a href="#bib-XML-NAMES" rel="biblioentry" class="bibref">
XML-NAMES
</a>
</cite>
]),
<a href="#dfn-compact_iri" title="compact_iri" class="tref internalDFN">
<ins class="diff-new">compact
</ins><abbr title="Internationalized Resource Identifier"><ins class="diff-new">
IRI
</ins></abbr></a>,<a href="#dfn-absolute_iri" title="absolute_iri" class="tref internalDFN"><ins class="diff-new">
absolute
</ins><abbr title="Internationalized Resource Identifier"><ins class="diff-new">
IRI
</ins></abbr></a>,
or
be
an
empty
string.
</p>
<p>
The
Web
uses
<a href="#dfn-iri" title="iri" class="tref internalDFN">
IRIs
</a>
for
unambiguous
identification.
The
idea
is
that
these
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>
s
mean
something
that
may
be
of
use
to
other
developers
and
that
it
is
useful
to
give
them
an
unambiguous
identifier.
That
is,
it
is
useful
for
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>
s
to
expand
to
IRIs
so
that
developers
don't
accidentally
step
on
each
other's
<a href="#dfn-vocabulary" title="vocabulary" class="tref internalDFN">
vocabulary
</a>
terms.
For
example,
the
term
<code>
name
</code>
may
map
directly
to
the
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
<code>
http://xmlns.com/foaf/0.1/name
</code>.
This
allows
JSON-LD
documents
to
be
constructed
using
the
common
JSON
practice
of
simple
name/value
pairs
while
ensuring
that
the
data
is
useful
outside
of
the
page,
API
or
database
in
which
it
resides.
The
value
of
a
term
mapping
<em title="must" class="rfc2119">
must
</em>
be
either;
1)
a
simple
string
with
the
lexical
form
of
an
absolute
<a href="#dfn-iri" title="iri" class="tref internalDFN">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
or,
2)
an
<a href="#dfn-json_object" title="json_object" class="tref internalDFN">
JSON
object
</a>
containing
an
<code>
@id
</code>,
<code>
@type
</code>,
<code>
<ins class="diff-new">@language
</ins></code>,
or
<code>
<del class="diff-old">@list
</del>
<ins class="diff-chg">@container
</ins>
</code>
keyword.
</p>
<p>
These
Linked
Data
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>
s
are
typically
collected
in
a
context
document
that
would
look
something
like
this:
</p>
<del class="diff-old">{
  &quot;@context&quot;:
  {
    &quot;name&quot;: &quot;http://xmlns.com/foaf/0.1/name&quot;,
    &quot;depiction&quot;:
    {
       &quot;@id&quot;: &quot;http://xmlns.com/foaf/0.1/depiction&quot;,
       &quot;@type&quot;: &quot;@id&quot;
    },
    &quot;homepage&quot;:
    {
       &quot;@id&quot;: &quot;http://xmlns.com/foaf/0.1/homepage&quot;,
       &quot;@type&quot;: &quot;@id&quot;
    },
  }
</del>
<pre class="example">{
<ins class="diff-chg">  "@context":
  {
    "name": "http://xmlns.com/foaf/0.1/name",
    "depiction":
    {
      "@id": "http://xmlns.com/foaf/0.1/depiction",
      "@type": "@id"
    },
    "homepage":
    {
      "@id": "http://xmlns.com/foaf/0.1/homepage",
      "@type": "@id"
    },
  }
</ins>
}
</pre>
<p>
This
context
document
can
then
be
used
in
an
JSON-LD
document
by
adding
a
single
line.
The
JSON
markup
as
shown
in
the
previous
section
could
be
changed
as
follows
to
link
to
the
context
document:
</p>
<del class="diff-old">{

  &quot;name&quot;: &quot;Manu Sporny&quot;,
  &quot;homepage&quot;: &quot;http://manu.sporny.org/&quot;,
  &quot;depiction&quot;: &quot;http://twitter.com/account/profile_image/manusporny&quot;
</del>
<pre class="example">{
  <span class="diff">"@context": "http://json-ld.org/contexts/person",</span>
<ins class="diff-chg">  "name": "Manu Sporny",
  "homepage": "http://manu.sporny.org/",
  "depiction": "http://twitter.com/account/profile_image/manusporny"
</ins>
}
</pre>
<p>
The
additions
above
transform
the
previous
JSON
document
into
a
JSON
document
with
added
semantics
because
the
<code>
@context
</code>
specifies
how
the
<strong>
name
</strong>,
<strong>
homepage
</strong>,
and
<strong>
depiction
</strong>
terms
map
to
<del class="diff-old">IRIs.
</del>
<a href="#dfn-iri" title="iri" class="tref internalDFN">
<ins class="diff-chg">IRIs
</ins></a>.
Mapping
those
keys
to
IRIs
gives
the
data
global
context.
If
two
developers
use
the
same
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
to
describe
a
property,
they
are
more
than
likely
expressing
the
same
concept.
This
allows
both
developers
to
re-use
each
others
data
without
having
to
agree
to
how
their
data
will
interoperate
on
a
site-by-site
basis.
Contexts
may
also
contain
type
information
for
certain
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>
s
as
well
as
other
processing
instructions
for
the
JSON-LD
processor.
</p>
<p>
Contexts
may
be
specified
in-line.
This
ensures
that
JSON-LD
documents
can
be
processed
when
a
JSON-LD
processor
does
not
have
access
to
the
Web.
</p>
<del class="diff-old">{
  &quot;@context&quot;:
  {
    &quot;name&quot;: &quot;http://xmlns.com/foaf/0.1/name&quot;,
    &quot;depiction&quot;:
    {
       &quot;@id&quot;: &quot;http://xmlns.com/foaf/0.1/depiction&quot;,
       &quot;@type&quot;: &quot;@id&quot;
    },
    &quot;homepage&quot;:
    {
       &quot;@id&quot;: &quot;http://xmlns.com/foaf/0.1/homepage&quot;,
       &quot;@type&quot;: &quot;@id&quot;
    },
  },
  &quot;name&quot;: &quot;Manu Sporny&quot;,
  &quot;homepage&quot;: &quot;http://manu.sporny.org/&quot;,
  &quot;depiction&quot;: &quot;http://twitter.com/account/profile_image/manusporny&quot;
</del>
<pre class="example">{
  <span class="diff">"@context":
<ins class="diff-chg">  {
    "name": "http://xmlns.com/foaf/0.1/name",
    "depiction":
    {
      "@id": "http://xmlns.com/foaf/0.1/depiction",
      "@type": "@id"
    },
    "homepage":
    {
      "@id": "http://xmlns.com/foaf/0.1/homepage",
      "@type": "@id"
    },
  },</span>
  "name": "Manu Sporny",
  "homepage": "http://manu.sporny.org/",
  "depiction": "http://twitter.com/account/profile_image/manusporny"
</ins>
}
</pre>
<p>
Contexts
<em title="may" class="rfc2119">
may
</em>
be
used
at
any
time
a
<a href="#dfn-json_object" title="json_object" class="tref internalDFN">
JSON
object
</a>
is
defined.
A
<a href="#dfn-json_object" title="json_object" class="tref internalDFN">
JSON
object
</a>
<em title="may" class="rfc2119">
may
</em>
specify
multiple
contexts,
using
an
<a href="#dfn-array" title="array" class="tref internalDFN">
array
</a>,
which
is
processed
in
array-order.
This
is
useful
when
an
author
would
like
to
use
an
existing
context
and
add
application-specific
terms
to
the
existing
context.
Duplicate
context
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>
s
<em title="must" class="rfc2119">
must
</em>
be
overridden
using
a
last-defined-overrides
mechanism.
</p>
<p>
The
set
of
contexts
defined
within
a
specific
<a href="#dfn-json_object" title="json_object" class="tref internalDFN">
JSON
Object
</a>
are
referred
to
as
<dfn id="dfn-local_context" title="local_context">
local
context
</dfn>
s.
The
<dfn id="dfn-active_context" title="active_context">
active
context
</dfn>
refers
to
the
accumulation
of
<a href="#dfn-local_context" title="local_context" class="tref internalDFN">
local
context
</a>
s
that
are
in
scope
at
a
specific
point
within
the
document.
The
following
example
specifies
an
external
context
and
then
layers
a
local
context
on
top
of
the
external
context:
</p>
<del class="diff-old">{
  &quot;@context&quot;: [
    &quot;http://json-ld.org/contexts/person&quot;,
    {
      &quot;pic&quot;: &quot;http://xmlns.com/foaf/0.1/depiction&quot;
    }
  ],
  &quot;name&quot;: &quot;Manu Sporny&quot;,
  &quot;homepage&quot;: &quot;http://manu.sporny.org/&quot;,

</del>
<pre class="example">{
  <span class="diff">"@context": [
<ins class="diff-chg">    "http://json-ld.org/contexts/person",
    {
      "pic": "http://xmlns.com/foaf/0.1/depiction"
    }
  ],</span>
  "name": "Manu Sporny",
  "homepage": "http://manu.sporny.org/",
</ins>  <span class="diff">"pic": "http://twitter.com/account/profile_image/manusporny"</span>
}
</pre>
<p>
JSON-LD
uses
a
special
type
of
machine-readable
document
called
a
<dfn id="dfn-vocabulary" title="vocabulary">
vocabulary
</dfn>
to
define
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>
s
that
are
then
used
to
describe
concepts
and
<del class="diff-old">&quot;things&quot;
</del>
<ins class="diff-chg">"things"
</ins>
in
the
world.
Typically,
these
<a href="#dfn-vocabulary" title="vocabulary" class="tref internalDFN">
vocabulary
</a>
documents
have
<a href="#dfn-prefix" title="prefix" class="tref internalDFN">
prefix
</a>
es
associated
with
them
and
contain
a
number
of
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>
declarations.
<a href="#dfn-prefix" title="prefix" class="tref internalDFN">
Prefix
</a>
es
are
helpful
when
a
developer
wants
to
mix
multiple
<a href="#dfn-vocabulary" title="vocabulary" class="tref internalDFN">
vocabularies
</a>
together
in
a
<a href="#dfn-context" title="context" class="tref internalDFN">
context
</a>,
but
does
not
want
to
go
to
the
trouble
of
defining
every
single
term
in
every
single
vocabulary.
Some
<del class="diff-old">Web
Vocabularies
</del>
<a href="#dfn-vocabulary" title="vocabulary" class="tref internalDFN">
<ins class="diff-chg">vocabularies
</ins></a>
may
have
dozens
of
terms
defined.
If
a
developer
wants
to
use
3-4
different
<a href="#dfn-vocabulary" title="vocabulary" class="tref internalDFN">
vocabularies
</a>,
the
number
of
terms
that
would
have
to
be
declared
in
a
single
<a href="#dfn-context" title="context" class="tref internalDFN">
context
</a>
could
become
quite
large.
To
reduce
the
number
of
different
terms
that
must
be
defined,
JSON-LD
also
allows
prefixes
to
be
used
to
<a href="#dfn-compact_iri" title="compact_iri" class="tref internalDFN">
compact
<del class="diff-old">IRIs.
</del>
<ins class="diff-chg">IRIs
</ins></a>.
</p>
<p>
For
example,
the
<a href="#dfn-iri" title="iri" class="tref internalDFN">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
<code>
http://xmlns.com/foaf/0.1/
</code>
specifies
a
<a href="#dfn-vocabulary" title="vocabulary" class="tref internalDFN">
vocabulary
</a>
which
may
be
represented
using
the
<code>
foaf
</code>
<a href="#dfn-prefix" title="prefix" class="tref internalDFN">
prefix
</a>.
The
<code>
foaf
</code>
vocabulary
contains
a
term
called
<strong>
name
</strong>.
If
you
join
the
<code>
foaf
</code>
<a href="#dfn-prefix" title="prefix" class="tref internalDFN">
prefix
</a>
with
the
<strong>
name
</strong>
suffix,
you
can
build
a
<a href="#dfn-compact_iri" title="compact_iri" class="tref internalDFN">
compact
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
that
will
expand
out
into
an
<a href="#dfn-absolute_iri" title="absolute_iri" class="tref internalDFN">
absolute
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
for
the
<code>
http://xmlns.com/foaf/0.1/name
</code>
<a href="#dfn-vocabulary" title="vocabulary" class="tref internalDFN">
vocabulary
</a>
term.
That
is,
the
compact
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
(or
short-form),
is
<code>
foaf:name
</code>
and
the
expanded-form
is
<code>
http://xmlns.com/foaf/0.1/name
</code>.
This
vocabulary
term
is
used
to
specify
a
person's
name.
</p>
<p>
Developers,
and
machines,
are
able
to
use
this
<a href="#dfn-iri" title="iri" class="tref internalDFN">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
(by
plugging
it
directly
into
a
web
browser,
for
instance)
to
go
to
the
term
and
get
a
definition
of
what
the
term
means.
Much
like
we
can
use
<a href="http://wordnet.princeton.edu/">
WordNet
</a>
today
to
see
the
definition
of
words
in
the
English
language.
Developers
and
machines
need
the
same
sort
of
definition
of
terms.
<a href="#dfn-iri" title="iri" class="tref internalDFN">
IRIs
</a>
provide
a
way
to
ensure
that
these
terms
are
unambiguous.
</p>
<p>
The
<a href="#dfn-context" title="context" class="tref internalDFN">
context
</a>
provides
a
collection
of
<a href="#dfn-vocabulary" title="vocabulary" class="tref internalDFN">
vocabulary
</a>
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>
s
<del class="diff-old">and
prefix
es
</del>
that
can
be
used
to
expand
JSON
keys
and
values
into
<del class="diff-old">IRI
s.
</del>
<a href="#dfn-iri" title="iri" class="tref internalDFN">
<ins class="diff-chg">IRIs
</ins></a>.
</p>
<p class="note">
To
ensure
the
best
possible
performance,
it
is
a
best
practice
to
put
the
<a href="#dfn-context" title="context" class="tref internalDFN">
context
</a>
definition
at
the
top
of
the
JSON-LD
document.
If
it
isn't
listed
first,
processors
have
to
save
each
key-value
pair
until
the
<a href="#dfn-context" title="context" class="tref internalDFN">
context
</a>
is
processed.
This
creates
a
memory
and
complexity
burden
for
one-pass
processors.
</p>
</div>
<div class="section" id="from-json-to-json-ld">
<h4>
<span class="secno">
2.2.2
</span>
From
JSON
to
JSON-LD
</h4>
<p>
If
a
set
of
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>
s
such
as,
<strong>
name
</strong>,
<strong>
homepage
</strong>,
and
<strong>
depiction
</strong>,
are
defined
in
a
<a href="#dfn-context" title="context" class="tref internalDFN">
context
</a>,
and
that
context
is
used
to
resolve
the
names
in
JSON
objects,
machines
are
able
to
automatically
expand
the
terms
to
something
meaningful
and
unambiguous,
like
this:
</p>
<del class="diff-old">{
  &quot;&quot;: &quot;Manu Sporny&quot;,
  &quot;&quot;: &quot;http://manu.sporny.org&quot;
  &quot;&quot;: &quot;http://twitter.com/account/profile_image/manusporny&quot;
</del>
<pre class="example">{
<ins class="diff-chg">  "<span class="diff">http://xmlns.com/foaf/0.1/name</span>": "Manu Sporny",
  "<span class="diff">http://xmlns.com/foaf/0.1/homepage</span>": "http://manu.sporny.org"
  "<span class="diff">http://rdfs.org/sioc/ns#avatar</span>": "http://twitter.com/account/profile_image/manusporny"
</ins>
}
</pre>
<p>
Doing
this
allows
JSON
to
be
unambiguously
machine-readable
without
requiring
developers
to
drastically
change
their
workflow.
</p>
<p class="note">
The
example
above
does
not
use
the
<code>
@id
</code>
keyword
to
set
the
<a href="#dfn-subject" title="subject" class="tref internalDFN">
subject
</a>
of
the
node
being
described
above.
This
type
of
node
is
called
an
<dfn id="dfn-unlabeled_node" title="unlabeled_node">
unlabeled
node
</dfn>
and
is
considered
to
be
a
weaker
form
of
<a href="#dfn-linked_data" title="linked_data" class="tref internalDFN">
Linked
Data
</a>.
It
is
advised
that
all
nodes
described
in
JSON-LD
are
given
unique
identifiers
via
the
<code>
@id
</code>
keyword
unless
the
data
is
not
intended
to
be
linked
to
from
other
data
sets.
</p>
</div>
</div>
</div>
<div class="section" id="basic-concepts">
<h2>
<span class="secno">
3.
</span>
Basic
Concepts
</h2>
<p>
JSON-LD
is
designed
to
ensure
that
<a href="#dfn-linked_data" title="linked_data" class="tref internalDFN">
Linked
Data
</a>
concepts
can
be
marked
up
in
a
way
that
is
simple
to
understand
and
create
by
Web
authors.
In
many
cases,
regular
JSON
markup
can
become
Linked
Data
with
the
simple
addition
of
a
<a href="#dfn-context" title="context" class="tref internalDFN">
context
</a>.
As
more
JSON-LD
features
are
used,
more
semantics
are
added
to
the
JSON
markup.
</p>
<div class="section" id="iris">
<h3>
<span class="secno">
3.1
</span>
IRIs
</h3>
<p>
Expressing
<a href="#dfn-iri" title="iri" class="tref internalDFN">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
s
are
fundamental
to
<a href="#dfn-linked_data" title="linked_data" class="tref internalDFN">
Linked
Data
</a>
as
that
is
how
most
<a href="#dfn-subject" title="subject" class="tref internalDFN">
subject
</a>
s,
all
<a href="#dfn-property" title="property" class="tref internalDFN">
properties
</a>
and
many
<a href="#dfn-object" title="object" class="tref internalDFN">
object
</a>
s
are
identified.
<a href="#dfn-iri" title="iri" class="tref internalDFN">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
s
can
be
expressed
in
a
variety
of
different
ways
in
JSON-LD.
</p>
<ol>
<li>
Except
within
a
<a href="#dfn-context" title="context" class="tref internalDFN">
context
</a>
definition,
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>
s
in
the
key
position
in
a
<a href="#dfn-json_object" title="json_object" class="tref internalDFN">
JSON
object
</a>
that
have
a
mapping
to
an
<a href="#dfn-absolute_iri" title="absolute_iri" class="tref internalDFN">
<ins class="diff-chg">absolute
</ins>
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
or
another
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>
in
the
<a href="#dfn-active_context" title="active_context" class="tref internalDFN">
active
context
</a>
are
expanded
to
an
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
by
JSON-LD
processors.
</li>
<li>
An
<a href="#dfn-iri" title="iri" class="tref internalDFN">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
is
generated
for
the
<a href="#dfn-string" title="string" class="tref internalDFN">
string
</a>
value
specified
using
<code>
@id
</code>
or
<code>
@type
</code>.
</li>
<li>
An
<a href="#dfn-iri" title="iri" class="tref internalDFN">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
is
generated
for
the
<a href="#dfn-string" title="string" class="tref internalDFN">
string
</a>
value
of
any
key
for
which
there
are
<a href="#dfn-coercion" title="coercion" class="tref internalDFN">
coercion
</a>
rules
in
effect
that
identify
the
value
as
an
<code>
@id
</code>.
</li>
</ol>
<p>
IRIs
may
be
represented
as
an
<a href="#dfn-absolute_iri" title="absolute_iri" class="tref internalDFN">
absolute
<abbr title="Internationalized Resource Identifier">
IRI
<del class="diff-old">,
</del>
</abbr>
</a>,
<ins class="diff-chg">a
</ins><a href="#dfn-relative_iri" title="relative_iri" class="tref internalDFN"><ins class="diff-chg">
relative
</ins><abbr title="Internationalized Resource Identifier"><ins class="diff-chg">
IRI
</ins></abbr></a>,<ins class="diff-chg">
a
</ins><a href="#dfn-term" title="term" class="tref internalDFN"><ins class="diff-chg">
term
</ins></a>,<ins class="diff-chg">
or
a
</ins><a href="#dfn-compact_iri" title="compact_iri" class="tref internalDFN"><ins class="diff-chg">
compact
</ins><abbr title="Internationalized Resource Identifier"><ins class="diff-chg">
IRI
</ins></abbr></a>.</p><p><ins class="diff-chg">
An
</ins><dfn id="dfn-absolute_iri" title="absolute_iri"><ins class="diff-chg">
absolute
</ins><abbr title="Internationalized Resource Identifier"><ins class="diff-chg">
IRI
</ins></abbr></dfn><ins class="diff-chg">
is
defined
in
[
</ins><cite><a href="#bib-RFC3987" rel="biblioentry" class="bibref"><ins class="diff-chg">
RFC3987
</ins></a></cite><ins class="diff-chg">
]
containing
a
</ins><em><ins class="diff-chg">
scheme
</ins></em><ins class="diff-chg">
along
with
</ins><em><ins class="diff-chg">
path
</ins></em><ins class="diff-chg">
and
optional
</ins><em><ins class="diff-chg">
query
</ins></em><ins class="diff-chg">
and
fragment
segments.
A
</ins><dfn id="dfn-relative_iri" title="relative_iri"><ins class="diff-chg">
relative
</ins><abbr title="Internationalized Resource Identifier"><ins class="diff-chg">
IRI
</ins></abbr></dfn><ins class="diff-chg">
is
</ins>
an
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
that
is
relative
<del class="diff-old">to
</del>
<ins class="diff-chg">some
other
</ins><a href="#dfn-absolute_iri" title="absolute_iri" class="tref internalDFN"><ins class="diff-chg">
absolute
</ins><abbr title="Internationalized Resource Identifier"><ins class="diff-chg">
IRI
</ins></abbr></a><ins class="diff-chg">
;
in
the
case
of
JSON-LD
this
is
</ins>
the
base
location
of
the
<del class="diff-old">document,
a
term
,
or
a
prefix
:suffix
construct.
</del>
<ins class="diff-chg">document.
</ins>
</p>
<p>
IRIs
can
be
expressed
directly
in
the
key
position
like
so:
</p>
<del class="diff-old">{
...
  &quot;&quot;: &quot;Manu Sporny&quot;,
...
</del>
<pre class="example">{
<ins class="diff-chg">...
  "<span class="diff">http://xmlns.com/foaf/0.1/name</span>": "Manu Sporny",
...
</ins>
}
</pre>
<p>
In
the
example
above,
the
key
<code>
http://xmlns.com/foaf/0.1/name
</code>
is
interpreted
as
an
<a href="#dfn-iri" title="iri" class="tref internalDFN">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>,
as
opposed
to
being
interpreted
as
a
string.
</p>
<p>
Term
expansion
occurs
for
IRIs
if
the
value
matches
a
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>
defined
within
the
<a href="#dfn-active_context" title="active_context" class="tref internalDFN">
active
context
</a>:
</p>
<del class="diff-old">{
  &quot;&quot; },
...
  &quot;&quot;: &quot;Manu Sporny&quot;,
...
</del>
<pre class="example">{
<ins class="diff-chg">  "<span class="diff">@context</span>":
  {
    "<span class="diff">name</span>": "<span class="diff">http://xmlns.com/foaf/0.1/name</span>"
...
  },
  "<span class="diff">name</span>": "Manu Sporny",
...
</ins>
}
</pre>
<p>
<a href="#dfn-prefix" title="prefix" class="tref internalDFN">
Prefix
</a>
es
are
expanded
when
the
form
of
the
value
<a href="#dfn-compact_iri" title="compact_iri" class="tref internalDFN">
<ins class="diff-new">compact
</ins><abbr title="Internationalized Resource Identifier"><ins class="diff-new">
IRI
</ins></abbr></a><ins class="diff-new">
represented
as
</ins>
is
<code>
prefix:suffix
</code>,
and
the
prefix
matches
a
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>
defined
within
the
<a href="#dfn-active_context" title="active_context" class="tref internalDFN">
active
context
</a>:
</p>
<del class="diff-old">{
  &quot;&quot; },
...
  &quot;&quot;: &quot;Manu Sporny&quot;,
...
</del>
<pre class="example">{
<ins class="diff-chg">  "<span class="diff">@context</span>":
  {
    "<span class="diff">foaf</span>": "<span class="diff">http://xmlns.com/foaf/0.1/</span>"
...
  },
  "<span class="diff">foaf:name</span>": "Manu Sporny",
...
</ins>
}
</pre>
<p>
<a href="#dfn-term" title="term" class="tref internalDFN">
Term
</a>
s
are
case
sensitive,
and
<em title="must" class="rfc2119">
must
</em>
be
matched
using
a
case-sensitive
comparison.
</p>
<p>
<ins class="diff-new">Keys
that
do
not
expand
to
an
absolute
</ins><abbr title="Internationalized Resource Identifier"><ins class="diff-new">
IRI
</ins></abbr><ins class="diff-new">
are
ignored.
</ins></p><p class="issue"><ins class="diff-new">
It
is
not
determined
if
processing
proceeds
into
values
of
undefined
keys.
If
so,
this
would
result
in
a
graph
which
is
not
</ins><a href="#dfn-embedding" title="embedding" class="tref internalDFN"><ins class="diff-new">
embedded
</ins></a>.</p><p>
<code>
foaf:name
</code>
above
will
automatically
expand
out
to
the
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
<code>
http://xmlns.com/foaf/0.1/name
</code>.
See
<del class="diff-old">Prefixes
</del>
<a href="#compact-iris">
<ins class="diff-chg">Compact
IRIs
</ins>
</a>
for
more
details.
</p>
<p>
An
<a href="#dfn-iri" title="iri" class="tref internalDFN">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
is
generated
when
a
value
is
associated
with
a
key
using
the
<code>
@id
</code>
keyword:
</p>
<del class="diff-old">{
...
  &quot;homepage&quot;: { &quot;&quot;: &quot;http://manu.sporny.org&quot; }
...
</del>
<pre class="example">{
<ins class="diff-chg">...
  "homepage": { "<span class="diff">@id</span>": "http://manu.sporny.org" }
...
</ins>
}
</pre>
<p class="note">
Specifying
a
<a href="#dfn-json_object" title="json_object" class="tref internalDFN">
JSON
Object
</a>
with
an
<code>
@id
</code>
key
is
used
to
identify
that
object
using
an
<a href="#dfn-iri" title="iri" class="tref internalDFN">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>.
This
facility
<em title="may" class="rfc2119">
may
</em>
also
be
used
to
link
a
<a href="#dfn-subject" title="subject" class="tref internalDFN">
subject
</a>
with
an
<a href="#dfn-object" title="object" class="tref internalDFN">
object
</a>
using
a
mechanism
called
<a href="#dfn-embedding" title="embedding" class="tref internalDFN">
embedding
</a>,
which
is
covered
in
the
section
titled
<a href="#embedding">
Embedding
</a>.
</p>
<p>
If
type
<a href="#dfn-coercion" title="coercion" class="tref internalDFN">
coercion
</a>
rules
are
specified
in
the
<code>
@context
</code>
for
a
particular
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>
or
property
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>,
an
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
is
generated:
</p>
<del class="diff-old">  &quot;@context&quot;:
  {
    ...
    &quot;homepage&quot;:
    {
      &quot;@id&quot;: &quot;http://xmlns.com/foaf/0.1/homepage&quot;,
      &quot;@type&quot;: &quot;@id&quot;
    }
    ...
  }
...
  &quot;homepage&quot;: &quot;http://manu.sporny.org/&quot;,
...
</del>
<pre class="example">{<span class="diff">
<ins class="diff-chg">  "@context":
  {
    ...
    "homepage":
    {
      "@id": "http://xmlns.com/foaf/0.1/homepage",
      "@type": "@id"
    }
    ...
  }</span>
...
  "homepage": "http://manu.sporny.org/",
...
</ins>
}
</pre>
<p>
Even
though
the
value
<code>
http://manu.sporny.org/
</code>
is
a
<a href="#dfn-string" title="string" class="tref internalDFN">
string
</a>,
the
type
<a href="#dfn-coercion" title="coercion" class="tref internalDFN">
coercion
</a>
rules
will
transform
the
value
into
an
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
when
processed
by
a
JSON-LD
Processor.
</p>
</div>
<div class="section" id="identifying-the-subject">
<h3>
<span class="secno">
3.2
</span>
Identifying
the
Subject
</h3>
<p>
To
be
able
to
externally
reference
nodes,
it
is
important
that
each
node
has
an
unambiguous
identifier.
<a href="#dfn-iri" title="iri" class="tref internalDFN">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
s
are
a
fundamental
concept
of
<a href="#dfn-linked_data" title="linked_data" class="tref internalDFN">
Linked
Data
</a>,
and
nodes
should
have
a
de-referencable
identifier
used
to
name
and
locate
them.
For
nodes
to
be
truly
linked,
de-referencing
the
identifier
should
result
in
a
representation
of
that
node.
Associating
an
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
with
a
node
tells
an
application
that
the
returned
document
contains
a
description
of
the
node
requested.
</p>
<p>
JSON-LD
documents
may
also
contain
descriptions
of
other
nodes,
so
it
is
necessary
to
be
able
to
uniquely
identify
each
node
which
may
be
externally
referenced.
</p>
<p>
A
<a href="#dfn-subject" title="subject" class="tref internalDFN">
subject
</a>
of
an
object
in
JSON
is
declared
using
the
<code>
@id
</code>
key.
The
subject
is
the
first
piece
of
information
needed
by
the
JSON-LD
processor
in
order
to
create
the
(subject,
property,
object)
tuple,
also
known
as
a
triple.
</p>
<del class="diff-old">{
...
  &quot;&quot;,
...
</del>
<pre class="example">{
<ins class="diff-chg">...
  "<span class="diff">@id</span>": "<span class="diff">http://example.org/people#joebob</span>",
...
</ins>
}
</pre>
<p>
The
example
above
would
set
the
subject
to
the
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
<code>
http://example.org/people#joebob
</code>.
</p>
<p class="note">
To
ensure
the
best
possible
performance,
it
is
a
best
practice
to
put
the
<code>
@id
</code>
keyword
before
other
key-value
pairs
in
an
object.
If
it
isn't
listed
first,
processors
have
to
save
each
key-value
pair
until
<code>
@id
</code>
is
processed
before
they
can
start
generating
triples.
Not
specifying
the
<code>
@id
</code>
keyword
first
creates
a
memory
and
complexity
burden
for
one-pass
processors.
</p>
</div>
<div class="section" id="specifying-the-type">
<h3>
<span class="secno">
3.3
</span>
Specifying
the
Type
</h3>
<p>
The
type
of
a
particular
subject
can
be
specified
using
the
<code>
@type
</code>
keyword.
Specifying
the
type
in
this
way
will
generate
a
triple
of
the
form
(subject,
type,
type-
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
).
To
be
considered
<a href="#dfn-linked_data" title="linked_data" class="tref internalDFN">
Linked
Data
</a>,
types
<em title="must" class="rfc2119">
must
</em>
be
uniquely
identified
by
an
<a href="#dfn-iri" title="iri" class="tref internalDFN">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>.
</p>
<del class="diff-old">{
...
  &quot;@id&quot;: &quot;http://example.org/people#joebob&quot;,
  &quot;&quot;,
...
</del>
<pre class="example">{
<ins class="diff-chg">...
  "@id": "http://example.org/people#joebob",
  "<span class="diff">@type</span>": "<span class="diff">http://xmlns.com/foaf/0.1/Person</span>",
...
</ins>
}
</pre>
</div>
<div class="section" id="strings">
<h3>
<span class="secno">
3.4
</span>
Strings
</h3>
<p>
Regular
text
strings,
also
referred
to
as
<dfn id="dfn-string_value" title="string_value">
string
value
</dfn>
s,
are
easily
expressed
using
regular
JSON
<a href="#dfn-string" title="string" class="tref internalDFN">
string
</a>
s.
</p>
<del class="diff-old">{
...
  &quot;name&quot;: &quot;&quot;,
...
</del>
<pre class="example">{
<ins class="diff-chg">...
  "name": "<span class="diff">Mark Birbeck</span>",
...
</ins>
}
</pre>
</div>
<div class="section" id="string-internationalization">
<h3>
<span class="secno">
3.5
</span>
String
Internationalization
</h3>
<p>
JSON-LD
makes
an
assumption
that
strings
with
associated
language
encoding
information
are
not
very
common
when
used
in
JavaScript
and
Web
Services.
Thus,
it
takes
a
little
more
effort
to
express
strings
with
associated
language
information.
</p>
<del class="diff-old">{
...
  &quot;name&quot;:
  {
    &quot;@value&quot;: &quot;花澄&quot;,
    &quot;@language&quot;: &quot;ja&quot;
  }
...
</del>
<pre class="example">{
<ins class="diff-chg">...
  "name": <span class="diff">
  {
    "@value": "花澄",
    "@language": "ja"
  }</span>
...
</ins>
}
</pre>
<p>
The
example
above
would
generate
a
<a href="#dfn-string_value" title="string_value" class="tref internalDFN">
string
value
</a>
for
<em>
花澄
</em>
and
associate
the
<code>
ja
</code>
language
code
with
the
triple
that
is
generated.
Languages
<em title="must" class="rfc2119">
must
</em>
be
expressed
in
[
<cite>
<a href="#bib-BCP47" rel="biblioentry" class="bibref">
BCP47
</a>
</cite>
]
format.
</p>
</div>
<div class="section" id="typed-values">
<h3>
<span class="secno">
3.6
</span>
Typed
Values
</h3>
<p>
A
value
with
an
associated
type,
also
known
as
a
<dfn id="dfn-typed_value" title="typed_value">
typed
value
</dfn>,
is
indicated
by
associating
a
value
with
an
<a href="#dfn-iri" title="iri" class="tref internalDFN">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
which
indicates
the
value's
type.
Typed
values
may
be
expressed
in
JSON-LD
in
three
ways:
</p>
<ol>
<li>
By
utilizing
the
<code>
@type
</code>
keyword
when
defining
a
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>
within
a
<code>
@context
</code>
section.
</li>
<li>
By
utilizing
the
expanded
form
for
specifying
objects.
</li>
<li>
By
using
a
native
JSON
type.
</li>
</ol>
<p>
The
first
example
uses
the
<code>
@type
</code>
keyword
to
express
a
typed
value:
</p>
<del class="diff-old">{
  &quot;@context&quot;: {
    &quot;xsd&quot;: &quot;http://www.w3.org/2001/XMLSchema#&quot;,
    &quot;modified&quot;: {
      &quot;@id&quot;: &quot;http://purl.org/dc/terms/modified&quot;,
      &quot;@type&quot;: &quot;xsd:dateTime&quot;
    }
  }
...
  &quot;modified&quot;: &quot;2010-05-29T14:17:39+02:00&quot;,
...
</del>
<pre class="example">{
  <span class="diff">"@context":
<ins class="diff-chg">  {
    "xsd": "http://www.w3.org/2001/XMLSchema#",
    "modified":
    {
      "@id": "http://purl.org/dc/terms/modified",
      "@type": "xsd:dateTime"
    }
  }</span>
...
  "modified": "2010-05-29T14:17:39+02:00",
...
</ins>
}
</pre>
<p>
The
second
example
uses
the
expanded
form
for
specifying
objects:
</p>
<del class="diff-old">{
...
  &quot;modified&quot;: {
    &quot;@value&quot;: &quot;2010-05-29T14:17:39+02:00&quot;,
    &quot;@type&quot;: &quot;xsd:dateTime&quot;
  }
...
</del>
<pre class="example">{
<ins class="diff-chg">...
  "modified":
</ins>  <span class="diff">{
<ins class="diff-chg">
    "@value": "2010-05-29T14:17:39+02:00",
    "@type": "xsd:dateTime"
  }</span>
...
</ins>
}
</pre>
<p>
Both
examples
above
would
generate
an
object
with
the
value
of
<code>
2010-05-29T14:17:39+02:00
</code>
and
the
type
of
<code>
http://www.w3.org/2001/XMLSchema#dateTime
</code>.
</p>
<p>
The
third
example
uses
a
built-in
native
JSON
type,
a
<a href="#dfn-number" title="number" class="tref internalDFN">
number
</a>,
to
express
a
type:
</p>
<del class="diff-old">{
...
  &quot;@id&quot;: &quot;http://example.org/people#joebob&quot;,
  &quot;age&quot;:
...
</del>
<pre class="example">{
<ins class="diff-chg">...
  "@id": "http://example.org/people#joebob",
  "age": <span class="diff">31</span>
...
</ins>
}
</pre>
<p>
The
example
above
is
really
just
a
shorthand
for
the
following:
</p>
<del class="diff-old">{
...
  &quot;@id&quot;: &quot;http://example.org/people#joebob&quot;,
  &quot;age&quot;: {
    &quot;@value&quot;: &quot;31&quot;,
    &quot;@type&quot;: &quot;http://www.w3.org/2001/XMLSchema#integer&quot;
  }
...
</del>
<pre class="example">{
<ins class="diff-chg">...
  "@id": "http://example.org/people#joebob",
  "age":
</ins>  <span class="diff">{
<ins class="diff-chg">
    "@value": "31",
    "@type": "http://www.w3.org/2001/XMLSchema#integer"
  }</span>
...
</ins>
}
</pre>
<p class="note">
The
<code>
@type
</code>
keyword
is
also
used
to
associate
a
type
with
a
<a href="#dfn-subject" title="subject" class="tref internalDFN">
subject
</a>.
Although
the
same
keyword
is
used
in
both
places,
the
concept
of
an
<em>
object
type
</em>
and
a
<em>
value
type
</em>
are
different.
This
is
similar
to
object-oriented
programming
languages
where
both
scalar
and
structured
types
use
the
same
class
inheritance
mechanism,
even
though
scalar
types
and
structured
types
are
inherently
different.
</p>
</div>
<div class="section" id="multiple-objects-for-a-single-property">
<h3>
<span class="secno">
3.7
</span>
Multiple
Objects
for
a
Single
Property
</h3>
<p>
A
JSON-LD
author
can
express
multiple
values
in
a
compact
way
by
using
<a href="#dfn-array" title="array" class="tref internalDFN">
array
</a>
s.
If
a
subject
has
multiple
values
for
the
same
property,
the
author
<em title="may" class="rfc2119">
may
</em>
express
each
property
as
an
<a href="#dfn-array" title="array" class="tref internalDFN">
array
</a>.
</p>
<p class="note">
In
JSON-LD,
multiple
objects
on
a
property
are
not
ordered.
This
is
because
graphs
are
inherently
unordered
data
structures.
To
learn
more
about
creating
ordered
collections
in
JSON-LD,
see
the
section
on
<a href="#lists">
Lists
</a>.
</p>
<del class="diff-old">{
...
  &quot;@id&quot;: &quot;http://example.org/people#joebob&quot;,
  &quot;nick&quot;: ,
...
</del>
<pre class="example">{
<ins class="diff-chg">...
  "@id": "http://example.org/people#joebob",
  "nick": <span class="diff">[ "joe", "bob", "jaybee" ]</span>,
...
</ins>
}
</pre>
<p>
The
markup
shown
above
would
generate
the
following
triples:
</p>
<del class="diff-old">&lt;http://example.org/people#joebob&gt;
   &lt;http://xmlns.com/foaf/0.1/nick&gt;
      &quot;joe&quot; .
&lt;http://example.org/people#joebob&gt;
   &lt;http://xmlns.com/foaf/0.1/nick&gt;
      &quot;bob&quot; .
&lt;http://example.org/people#joebob&gt;
   &lt;http://xmlns.com/foaf/0.1/nick&gt;
&quot;jaybee&quot;
</del>
<pre class="example">&lt;http://example.org/people#joebob&gt;
<ins class="diff-chg">   &lt;http://xmlns.com/foaf/0.1/nick&gt;
      "joe" .
&lt;http://example.org/people#joebob&gt;
   &lt;http://xmlns.com/foaf/0.1/nick&gt;
      "bob" .
&lt;http://example.org/people#joebob&gt;
   &lt;http://xmlns.com/foaf/0.1/nick&gt;
"jaybee"
</ins>
.
</pre>
</div>
<div class="section" id="multiple-values-for-a-single-property">
<h3>
<span class="secno">
3.8
</span>
Multiple
Values
for
a
Single
Property
</h3>
<p>
Multiple
<a href="#dfn-value" title="value" class="tref internalDFN">
value
</a>
s
may
also
be
expressed
using
the
expanded
form
for
<a href="#dfn-object" title="object" class="tref internalDFN">
object
</a>
s:
</p>
<del class="diff-old">{
  &quot;@id&quot;: &quot;http://example.org/articles/8&quot;,
  &quot;dc:title&quot;:
  [
    {&quot;@value&quot;: &quot;Das Kapital&quot;, &quot;@language&quot;: &quot;de&quot;},
    {&quot;@value&quot;: &quot;Capital&quot;, &quot;@language&quot;: &quot;en&quot;}
  ]
</del>
<pre class="example">{
<ins class="diff-chg">  "@id": "http://example.org/articles/8",
  "dc:title": <span class="diff">
  [
    {
      "@value": "Das Kapital",
      "@language": "de"
    },
    {
      "@value": "Capital",
      "@language": "en"
    }
  ]</span>
</ins>
}
</pre>
<p>
The
markup
shown
above
would
generate
the
following
triples:
</p>
<del class="diff-old">&lt;http://example.org/articles/8&gt;
   &lt;http://purl.org/dc/terms/title&gt;
      &quot;Das Kapital&quot;@de .
&lt;http://example.org/articles/8&gt;
   &lt;http://purl.org/dc/terms/title&gt;
&quot;Capital&quot;@en
</del>
<pre class="example">&lt;http://example.org/articles/8&gt;
<ins class="diff-chg">   &lt;http://purl.org/dc/terms/title&gt;
      "Das Kapital"@de .
&lt;http://example.org/articles/8&gt;
   &lt;http://purl.org/dc/terms/title&gt;
"Capital"@en
</ins>
.
</pre>
</div>
<div class="section" id="lists">
<h3>
<span class="secno">
3.9
</span>
Lists
</h3>
<p>
Because
graphs
do
not
describe
ordering
for
links
between
nodes,
in
contrast
to
plain
JSON,
multi-valued
properties
in
JSON-LD
do
not
provide
an
ordering
of
the
listed
objects.
For
example,
consider
the
following
simple
document:
</p>
<del class="diff-old">  {
...
  &quot;@id&quot;: &quot;http://example.org/people#joebob&quot;,
  &quot;nick&quot;: ,
...
</del>
  <pre class="example">{
<ins class="diff-chg">...
  "@id": "http://example.org/people#joebob",
  "nick": <span class="diff">[ "joe", "bob", "jaybee" ]</span>,
...
</ins>
}
</pre>
<p>
This
results
in
three
triples
being
generated,
each
relating
the
subject
to
an
individual
object,
with
no
inherent
order.
</p>
<p>
As
the
notion
of
ordered
collections
is
rather
important
in
data
modeling,
it
is
useful
to
have
specific
language
support.
In
JSON-LD,
a
list
may
be
represented
using
the
<code>
@list
</code>
keyword
as
follows:
</p>
<del class="diff-old">  {
...
  &quot;@id&quot;: &quot;http://example.org/people#joebob&quot;,
  &quot;foaf:nick&quot;: ,
...
</del>
  <pre class="example">{
<ins class="diff-chg">...
  "@id": "http://example.org/people#joebob",
  "foaf:nick":
</ins>  <span class="diff">{
<ins class="diff-chg">
    "@list": [ "joe", "bob", "jaybee" ]
  }</span>,
...
</ins>
}
</pre>
<p>
This
describes
the
use
of
this
<a href="#dfn-array" title="array" class="tref internalDFN">
array
</a>
as
being
ordered,
and
order
is
maintained
through
alternate
representations
as
described
in
[
<cite>
<a href="#bib-JSON-LD-API" rel="biblioentry" class="bibref">
JSON-LD-API
</a>
</cite>
].
If
every
use
of
a
given
multi-valued
property
is
a
list,
this
may
be
abbreviated
by
<del class="diff-old">adding
a
</del>
<ins class="diff-chg">setting
</ins>
<code>
<del class="diff-old">@type
</del>
<ins class="diff-chg">@container
</ins>
</code>
<del class="diff-old">coercion
</del>
<ins class="diff-chg">to
</ins><code><ins class="diff-chg">
@list
</ins></code><ins class="diff-chg">
in
the
</ins><a href="#dfn-context" title="context" class="tref internalDFN"><ins class="diff-chg">
context
</ins>
</a>:
</p>
<del class="diff-old">  {
  &quot;@context&quot;: {
    ...
    &quot;nick&quot;: {
      &quot;@id&quot;: &quot;http://xmlns.com/foaf/0.1/nick&quot;,
      &quot;@list&quot;: true
    }
},
...
  &quot;@id&quot;: &quot;http://example.org/people#joebob&quot;,
  &quot;nick&quot;: ,
...
</del>
  <pre class="example">{
  <span class="diff">"@context":
<ins class="diff-chg">  {
    ...
    "nick":
    {
      "@id": "http://xmlns.com/foaf/0.1/nick",
      "@container": "@list"
    }
  }</span>,
...
  "@id": "http://example.org/people#joebob",
  "nick": <span class="diff">[ "joe", "bob", "jaybee" ]</span>,
...
</ins>
}
</pre>
<p>
List
coercion
is
specified
within
an
expanded
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>
definition
using
the
<code>
<del class="diff-old">@list
</del>
<ins class="diff-chg">@container
</ins>
</code>
key.
The
value
of
this
key,
if
present,
<em title="must" class="rfc2119">
must
</em>
be
<code>
<del class="diff-old">true
</del>
<ins class="diff-chg">@list
</ins>
</code>.
This
indicates
that
array
values
of
keys
coerced
as
<code>
@list
</code>
are
to
be
serialized
as
a
<a href="#lists">
List
</a>.
</p>
<p class="note">
<ins class="diff-new">List
of
lists
are
not
allowed
in
this
version
of
JSON-LD.
If
a
list
of
lists
is
detected,
a
JSON-LD
processor
will
throw
an
exception.
</ins></p>
</div>
</div>
<div class="section" id="advanced-concepts">
<h2>
<span class="secno">
4.
</span>
Advanced
Concepts
</h2>
<p>
JSON-LD
has
a
number
of
features
that
provide
functionality
above
and
beyond
the
core
functionality
described
above.
The
following
sections
outline
the
features
that
are
specific
to
JSON-LD.
</p>
<div class="section" id="compact-iris">
<h3>
<span class="secno">
4.1
</span>
<del class="diff-old">Prefixes
</del>
<ins class="diff-chg">Compact
IRIs
</ins>
</h3>
<p>
<a href="#dfn-term" title="term" class="tref internalDFN">
Term
</a>
s
in
<a href="#dfn-linked_data" title="linked_data" class="tref internalDFN">
Linked
Data
</a>
documents
may
draw
from
a
number
of
different
<a href="#dfn-vocabulary" title="vocabulary" class="tref internalDFN">
vocabularies
</a>.
At
times,
declaring
every
single
term
that
a
document
uses
can
require
the
developer
to
declare
tens,
if
not
hundreds
of
potential
<a href="#dfn-vocabulary" title="vocabulary" class="tref internalDFN">
vocabulary
</a>
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>
s
that
are
used
across
an
application.
This
is
a
concern
for
at
least
three
reasons;
the
first
is
the
cognitive
load
on
the
developer
of
remembering
all
of
the
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>
s,
the
second
is
the
serialized
size
of
the
<a href="#dfn-context" title="context" class="tref internalDFN">
context
</a>
if
it
is
specified
inline,
the
third
is
future-proofing
embedded
application
<a href="#dfn-context" title="context" class="tref internalDFN">
context
</a>
s
that
may
not
be
easy
to
change
after
they
are
deployed.
In
order
to
address
these
issues,
the
concept
of
a
<del class="diff-old">prefix
</del>
<a href="#dfn-compact_iri" title="compact_iri" class="tref internalDFN">
<ins class="diff-chg">compact
</ins><abbr title="Internationalized Resource Identifier"><ins class="diff-chg">
IRI
</ins></abbr>
</a>
<del class="diff-old">mechanism
</del>
is
introduced.
</p>
<p>
A
<del class="diff-old">prefix
</del>
<dfn id="dfn-compact_iri" title="compact_iri">
<ins class="diff-chg">compact
</ins><abbr title="Internationalized Resource Identifier"><ins class="diff-chg">
IRI
</ins></abbr>
</dfn>
is
a
<del class="diff-old">compact
</del>
way
of
expressing
<del class="diff-old">a
base
</del>
<ins class="diff-chg">an
</ins><a href="#dfn-iri" title="iri" class="tref internalDFN">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
<del class="diff-old">for
</del>
<ins class="diff-chg">using
</ins>
a
<del class="diff-old">vocabulary
.
</del>
<em>
<ins class="diff-chg">prefix
</ins></em><ins class="diff-chg">
and
</ins><em><ins class="diff-chg">
suffix
</ins></em>.
Generally,
these
prefixes
are
used
by
concatenating
the
<em>
prefix
</em>
and
a
<em>
suffix
</em>,
which
is
separated
by
a
colon
(
<code>:
</code>
).
The
<dfn id="dfn-prefix" title="prefix">
prefix
</dfn>
is
a
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>
taken
from
the
<a href="#dfn-active_context" title="active_context" class="tref internalDFN">
active
context
</a>
and
is
a
short
string
identifying
a
particular
<a href="#dfn-iri" title="iri" class="tref internalDFN">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
in
a
JSON-LD
document.
For
example,
the
prefix
<code>
foaf
</code>
may
be
used
as
a
short
hand
for
the
Friend-of-a-Friend
vocabulary,
which
is
identified
using
the
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
<code>
http://xmlns.com/foaf/0.1/
</code>.
A
developer
may
append
any
of
the
FOAF
<a href="#dfn-vocabulary" title="vocabulary" class="tref internalDFN">
vocabulary
</a>
terms
to
the
end
of
the
prefix
to
specify
a
short-hand
version
of
the
<a href="#dfn-absolute_iri" title="absolute_iri" class="tref internalDFN">
absolute
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
for
the
<a href="#dfn-vocabulary" title="vocabulary" class="tref internalDFN">
vocabulary
</a>
term.
For
example,
<code>
foaf:name
</code>
would
be
expanded
out
to
the
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
<code>
http://xmlns.com/foaf/0.1/name
</code>.
Instead
of
having
to
remember
and
type
out
the
entire
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>,
the
developer
can
instead
use
the
prefix
in
their
JSON-LD
markup.
</p>
<p>
<del class="diff-old">To
generate
an
</del>
<ins class="diff-chg">Terms
are
interpreted
as
</ins><a href="#dfn-compact_iri" title="compact_iri" class="tref internalDFN"><ins class="diff-chg">
compact
</ins>
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
<del class="diff-old">out
of
a
</del>
<ins class="diff-chg">s
if
they
contain
at
least
one
colon
and
the
first
colon
is
not
followed
by
two
slashes
(
</ins>
<code>
<del class="diff-old">prefix:suffix
</del>
<ins class="diff-chg">//
</ins></code>,<ins class="diff-chg">
as
in
</ins><code><ins class="diff-chg">
http://example.com
</ins>
</code>
<del class="diff-old">construct,
</del>
<ins class="diff-chg">).
To
generate
the
full
</ins><a href="#dfn-iri" title="iri" class="tref internalDFN"><abbr title="Internationalized Resource Identifier"><ins class="diff-chg">
IRI
</ins></abbr></a>,
the
value
is
first
split
into
a
<em>
prefix
</em>
and
<em>
suffix
</em>
at
the
first
occurrence
of
a
colon
(
<code>:
</code>
).
If
the
<a href="#dfn-active_context" title="active_context" class="tref internalDFN">
active
context
</a>
contains
a
term
mapping
for
<em>
prefix
</em>,
an
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
is
generated
by
prepending
the
mapped
<em>
prefix
</em>
to
the
(possibly
empty)
<em>
suffix
</em>
using
textual
concatenation.
If
no
prefix
mapping
is
defined,
the
value
is
used
directly
as
an
<a href="#dfn-absolute_iri" title="absolute_iri" class="tref internalDFN">
<ins class="diff-new">absolute
</ins>
<abbr title="Internationalized Resource Identifier">
IRI
<del class="diff-old">.
</del>
</abbr>
</a>.
If
the
prefix
is
an
underscore
(
<code>
_
</code>
),
the
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
remains
unchanged.
<ins class="diff-new">This
effectively
means
that
every
term
containing
a
colon
will
be
interpreted
by
a
JSON-LD
processor
as
an
</ins><abbr title="Internationalized Resource Identifier"><ins class="diff-new">
IRI
</ins></abbr>.
</p>
<p>
The
ability
to
use
<del class="diff-old">prefix
</del>
<a href="#dfn-compact_iri" title="compact_iri" class="tref internalDFN">
<ins class="diff-chg">compact
IRIs
</ins>
</a>
<del class="diff-old">es
</del>
reduces
the
need
for
developers
to
declare
every
<a href="#dfn-vocabulary" title="vocabulary" class="tref internalDFN">
vocabulary
</a>
term
that
they
intend
to
use
in
the
JSON-LD
<a href="#dfn-context" title="context" class="tref internalDFN">
context
</a>.
This
reduces
stand-alone
JSON-LD
document
serialization
size
because
every
<a href="#dfn-vocabulary" title="vocabulary" class="tref internalDFN">
vocabulary
</a>
term
need
not
be
declared
in
the
embedded
context.
<del class="diff-old">Prefix
</del>
<a href="#dfn-compact_iri" title="compact_iri" class="tref internalDFN">
<ins class="diff-chg">Compact
IRIs
</ins>
</a>
also
reduces
the
cognitive
load
on
the
developer.
It
is
far
easier
to
remember
<code>
foaf:name
</code>
than
it
is
to
remember
<code>
http://xmlns.com/foaf/0.1/name
</code>.
The
use
of
prefixes
also
ensures
that
a
<a href="#dfn-context" title="context" class="tref internalDFN">
context
</a>
document
does
not
have
to
be
updated
in
lock-step
with
an
externally
defined
<a href="#dfn-vocabulary" title="vocabulary" class="tref internalDFN">
vocabulary
</a>.
Without
prefixes,
a
developer
would
need
to
keep
their
application
context
terms
in
lock-step
with
an
externally
defined
vocabulary.
Rather,
by
just
declaring
the
<a href="#dfn-vocabulary" title="vocabulary" class="tref internalDFN">
vocabulary
</a>
prefix,
one
can
use
new
terms
as
they're
declared
without
having
to
update
the
application's
JSON-LD
<a href="#dfn-context" title="context" class="tref internalDFN">
context
</a>.
</p>
<p>
Consider
the
following
example:
</p>
<del class="diff-old">  {
  &quot;@context&quot;: {


  },
  &quot;@id&quot;: &quot;http://example.org/library&quot;,
  &quot;@type&quot;: ,
  : {
    &quot;@id&quot;: &quot;http://example.org/library/the-republic&quot;,
    &quot;@type&quot;: ,
    : &quot;Plato&quot;,
    : &quot;The Republic&quot;,
    : {
      &quot;@id&quot;: &quot;http://example.org/library/the-republic#introduction&quot;,
      &quot;@type&quot;: ,
      : &quot;An introductory chapter on The Republic.&quot;,
      : &quot;The Introduction&quot;
    }
  }
</del>
  <pre class="example">{
<ins class="diff-chg">  "@context":
  {
</ins>    <span class="diff">"dc": "http://purl.org/dc/elements/1.1/",</span>
    <span class="diff">"ex": "http://example.org/vocab#"</span>
<ins class="diff-chg">
  },
  "@id": "http://example.org/library",
  "@type": <span class="diff">"ex:Library"</span>,
</ins>  <span class="diff">"ex:contains"</span>:
<ins class="diff-chg">
  {
    "@id": "http://example.org/library/the-republic",
    "@type": <span class="diff">"ex:Book"</span>,
</ins>    <span class="diff">"dc:creator"</span>: "Plato",
    <span class="diff">"dc:title"</span>: "The Republic",
    <span class="diff">"ex:contains"</span>:
<ins class="diff-chg">
    {
      "@id": "http://example.org/library/the-republic#introduction",
      "@type": <span class="diff">"ex:Chapter"</span>,
</ins>      <span class="diff">"dc:description"</span>: "An introductory chapter on The Republic.",
      <span class="diff">"dc:title"</span>: "The Introduction"
<ins class="diff-chg">
    }
  }
</ins>
}
</pre>
<p>
In
this
example,
two
different
<a href="#dfn-vocabulary" title="vocabulary" class="tref internalDFN">
vocabularies
</a>
are
referred
to
using
prefixes.
Those
prefixes
are
then
used
as
type
and
property
values
using
the
<ins class="diff-new">compact
</ins><abbr title="Internationalized Resource Identifier"><ins class="diff-new">
IRI
</ins></abbr>
<code>
prefix:suffix
</code>
notation.
</p>
<p>
<del class="diff-old">Prefixes,
</del>
<ins class="diff-chg">It's
also
possible
to
use
compact
IRIs
within
the
context
as
shown
in
the
following
example:
</ins></p><p>  </p><pre class="example">{
<ins class="diff-chg">
  "@context":
  {
    "xsd": "http://www.w3.org/2001/XMLSchema#",
    "foaf": "http://xmlns.com/foaf/0.1/",
</ins>    <span class="diff">"foaf:homepage"</span>: { "@type": "@id" },
<ins class="diff-chg">
    "picture": { "@id": <span class="diff">"foaf:depiction"</span>, "@type": "@id" }
  },
  "@subject": "http://me.markus-lanthaler.com/",
  "@type": "foaf:Person",
  "foaf:name": "Markus Lanthaler",
  "foaf:homepage": "http://www.markus-lanthaler.com/",
  "picture": "http://twitter.com/account/profile_image/markuslanthaler"
}
</ins></pre><p><a href="#dfn-compact_iri" title="compact_iri" class="tref internalDFN"><ins class="diff-chg">
Compact
IRIs
</ins></a>,
also
known
as
CURIEs,
are
defined
more
formally
in
RDFa
Core
1.1,
<cite>
<a href="http://www.w3.org/TR/rdfa-core/#s_curies">
Section
6
<del class="diff-old">&quot;CURIE
</del>
<ins class="diff-chg">"CURIE
</ins>
Syntax
<del class="diff-old">Definition&quot;
</del>
<ins class="diff-chg">Definition"
</ins>
</a>
</cite>
[
<cite>
<a href="#bib-RDFA-CORE" rel="biblioentry" class="bibref">
RDFA-CORE
</a>
</cite>
].
JSON-LD
does
not
support
the
square-bracketed
CURIE
syntax
as
the
mechanism
is
not
required
to
disambiguate
<a href="#dfn-iri" title="iri" class="tref internalDFN">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
s
in
a
JSON-LD
document
like
it
is
in
HTML
documents.
</p>
</div>
<div class="section" id="external-contexts">
<h3>
<span class="secno">
4.2
</span>
External
Contexts
</h3>
<p>
Authors
may
choose
to
declare
JSON-LD
<a href="#dfn-context" title="context" class="tref internalDFN">
context
</a>
s
in
external
documents
to
promote
re-use
of
contexts
as
well
as
reduce
the
size
of
JSON-LD
documents.
</p>
<p>
In
order
to
use
an
external
context,
an
author
<del class="diff-old">may
</del>
<em title="must" class="rfc2119">
<ins class="diff-chg">must
</ins>
</em>
specify
an
<a href="#dfn-iri" title="iri" class="tref internalDFN">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
to
a
valid
JSON-LD
document.
The
referenced
document
<em title="must" class="rfc2119">
must
</em>
have
a
top-level
<a href="#dfn-json_object" title="json_object" class="tref internalDFN">
JSON
Object
</a>.
The
value
of
any
<code>
@context
</code>
key
within
that
object
is
substituted
for
the
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
within
the
referencing
document
to
have
the
same
effect
as
if
the
value
were
specified
inline
within
the
referencing
document.
</p>
<p>
The
following
example
demonstrates
the
use
of
an
external
context:
</p>
<del class="diff-old">{
  ,
  &quot;name&quot;: &quot;Manu Sporny&quot;,
  &quot;homepage&quot;: &quot;http://manu.sporny.org/&quot;,
  &quot;depiction&quot;: &quot;http://twitter.com/account/profile_image/manusporny&quot;
</del>
<pre class="example">{
  <span class="diff">"@context": "http://json-ld.org/contexts/person"</span>,
<ins class="diff-chg">  "name": "Manu Sporny",
  "homepage": "http://manu.sporny.org/",
  "depiction": "http://twitter.com/account/profile_image/manusporny"
</ins>
}
</pre>
<p>
Authors
may
also
import
multiple
contexts
or
a
combination
of
external
and
local
contexts
by
specifying
a
list
of
contexts:
</p>
<del class="diff-old">{
  &quot;@context&quot;:
  [
    &quot;http://json-ld.org/contexts/person&quot;,
    { &quot;foaf&quot;: &quot;http://xmlns.com/foaf/0.1/&quot; },
    &quot;http://json-ld.org/contexts/event&quot;,
  ]
  &quot;name&quot;: &quot;Manu Sporny&quot;,
  &quot;homepage&quot;: &quot;http://manu.sporny.org/&quot;,
  &quot;depiction&quot;: &quot;http://twitter.com/account/profile_image/manusporny&quot;
  &quot;celebrates&quot;:
  {
    &quot;@type&quot;: &quot;Event&quot;,
    &quot;description&quot;: &quot;International Talk Like a Pirate Day&quot;,
    &quot;date&quot;: &quot;R/2011-09-19&quot;
  }
</del>
<pre class="example">{
  <span class="diff">"@context":
<ins class="diff-chg">  [
    "http://json-ld.org/contexts/person",
    {
      "foaf": "http://xmlns.com/foaf/0.1/"
    },
    "http://json-ld.org/contexts/event",
  ]</span>
  "name": "Manu Sporny",
  "homepage": "http://manu.sporny.org/",
  "depiction": "http://twitter.com/account/profile_image/manusporny"
</ins>  <span class="diff">"celebrates":
<ins class="diff-chg">
  {
    "@type": "Event",
    "description": "International Talk Like a Pirate Day",
    "date": "R/2011-09-19"
  }</span>
</ins>
}
</pre>
<p>
Each
context
in
a
list
will
be
evaluated
in-order.
Duplicate
mappings
among
the
<a href="#dfn-context" title="context" class="tref internalDFN">
context
</a>
s
<em title="must" class="rfc2119">
must
</em>
be
overwritten
on
a
last-defined-overrides
basis.
The
context
list
<em title="must" class="rfc2119">
must
</em>
contain
either
de-referenceable
<a href="#dfn-iri" title="iri" class="tref internalDFN">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
s
or
<a href="#dfn-json_object" title="json_object" class="tref internalDFN">
JSON
Object
</a>
s
that
conform
to
the
<a href="#dfn-context" title="context" class="tref internalDFN">
context
</a>
syntax
as
described
in
this
document.
</p>
<p>
An
author
may
nest
contexts
within
<a href="#dfn-json_object" title="json_object" class="tref internalDFN">
JSON
object
</a>
s,
with
the
more
deeply
nested
contexts
overriding
the
values
in
previously
defined
contexts:
</p>
<del class="diff-old">{
  &quot;@context&quot;:
  {
    &quot;name&quot;: &quot;http://example.com/person#name&quot;,
    &quot;details&quot;: &quot;http://example.com/person#details&quot;
  },
  &quot;&quot;: &quot;Markus&quot;,
  ...
  &quot;details&quot;:
  {

    &quot;&quot;: &quot;Acme, Ltd.&quot;
  }
</del>
<pre class="example">{
  <span class="diff">"@context":
<ins class="diff-chg">  {
    "name": "http://example.com/person#name",
    "details": "http://example.com/person#details"
  },</span>
  "<span class="diff">name</span>": "Markus Lanthaler",
  ...
  "details":
  {
</ins>    <span class="diff">"@context": { "name": "http://example.com/organization#name" },</span>
<ins class="diff-chg">
    "<span class="diff">name</span>": "Graz University of Technology"
  }
</ins>
}
</pre>
<p>
In
the
example
above,
the
<code>
name
</code>
prefix
is
overridden
in
the
more
deeply
nested
<code>
details
</code>
structure.
Note
that
this
is
rarely
a
good
authoring
practice
and
is
typically
used
when
the
JSON
object
has
legacy
applications
using
the
structure
of
the
object.
</p>
<p>
External
JSON-LD
context
documents
<em title="may" class="rfc2119">
may
</em>
contain
extra
information
located
outside
of
the
<code>
@context
</code>
key,
such
as
documentation
about
the
<del class="diff-old">prefix
</del>
<a href="#dfn-prefix" title="prefix" class="tref internalDFN">
<ins class="diff-chg">prefixes
</ins>
</a>
<del class="diff-old">es
</del>
declared
in
the
document.
When
importing
a
<code>
@context
</code>
value
from
an
external
JSON-LD
context
document,
any
extra
information
contained
outside
of
the
<code>
@context
</code>
value
<em title="must" class="rfc2119">
must
</em>
be
discarded.
It
is
also
<em title="recommended" class="rfc2119">
recommended
</em>
that
a
human-readable
document
encoded
in
HTML+RDFa
[
<cite>
<a href="#bib-HTML-RDFA" rel="biblioentry" class="bibref">
HTML-RDFA
</a>
</cite>
]
or
other
Linked
Data
compatible
format
is
served
as
well
to
explain
the
correct
usage
of
the
JSON-LD
context
document.
</p>
</div>
<div class="section" id="referencing-contexts-from-json-documents">
<h3>
<span class="secno">
4.3
</span>
<ins class="diff-new">Referencing
Contexts
from
JSON
Documents
</ins></h3><p><ins class="diff-new">
Ordinary
JSON
documents
can
be
transformed
in
JSON-LD
documents
by
referencing
to
an
external
JSON-LD
</ins><a href="#dfn-context" title="context" class="tref internalDFN"><ins class="diff-new">
context
</ins></a><ins class="diff-new">
in
an
HTTP
Link
Header.
Doing
this
allows
JSON
to
be
unambiguously
machine-readable
without
requiring
developers
to
drastically
change
their
workflow
and
provides
an
upgrade
path
for
existing
infrastructure
without
breaking
existing
clients
that
rely
on
the
</ins><code><ins class="diff-new">
application/json
</ins></code><ins class="diff-new">
media
type.
</ins></p><p><ins class="diff-new">
In
order
to
use
an
external
context
with
an
ordinary
JSON
document,
an
author
</ins><em title="must" class="rfc2119"><ins class="diff-new">
must
</ins></em><ins class="diff-new">
specify
an
</ins><a href="#dfn-iri" title="iri" class="tref internalDFN"><abbr title="Internationalized Resource Identifier"><ins class="diff-new">
IRI
</ins></abbr></a><ins class="diff-new">
to
a
valid
JSON-LD
document
in
an
HTTP
Link
Header
[
</ins><cite><a href="#bib-RFC5988" rel="biblioentry" class="bibref"><ins class="diff-new">
RFC5988
</ins></a></cite><ins class="diff-new">
]
using
the
</ins><code><ins class="diff-new">
describedby
</ins></code><ins class="diff-new">
link
relation.
The
referenced
document
</ins><em title="must" class="rfc2119"><ins class="diff-new">
must
</ins></em><ins class="diff-new">
have
a
top-level
</ins><a href="#dfn-json_object" title="json_object" class="tref internalDFN"><ins class="diff-new">
JSON
Object
</ins></a>.<ins class="diff-new">
The
</ins><code><ins class="diff-new">
@context
</ins></code><ins class="diff-new">
subtree
within
that
object
is
added
to
the
top-level
object
of
the
referencing
document.
If
an
array
is
at
the
top-level
of
the
referencing
document
and
its
items
are
objects,
the
</ins><code><ins class="diff-new">
@context
</ins></code><ins class="diff-new">
subtree
is
added
to
all
array
items.
All
extra
information
located
outside
of
the
</ins><code><ins class="diff-new">
@context
</ins></code><ins class="diff-new">
subtree
in
the
referenced
document
</ins><em title="must" class="rfc2119"><ins class="diff-new">
must
</ins></em><ins class="diff-new">
be
discarded.
</ins></p><p><ins class="diff-new">
The
following
example
demonstrates
the
use
of
an
external
context
with
an
ordinary
JSON
document:
</ins></p><pre class="example">GET /ordinary-json-document.json HTTP/1.1
<ins class="diff-new">
Host: example.com
Accept: application/json,*/*;q=0.1

----------------------------------------------------

HTTP/1.0 200 OK
...
Content-Type: application/json
</ins><span class="diff">Link: &lt;http://json-ld.org/contexts/person&gt;; rel="describedby"; type="application/ld+json"</span>
<ins class="diff-new">

{
  "name": "Markus Lanthaler",
  "homepage": "http://www.markus-lanthaler.com/",
  "depiction": "http://twitter.com/account/profile_image/markuslanthaler"
}
</ins></pre><p class="note"><ins class="diff-new">
JSON-LD
documents
</ins><em title="must" class="rfc2119"><ins class="diff-new">
must
</ins></em><ins class="diff-new">
have
all
context
information,
including
references
to
external
contexts,
within
the
body
of
the
document.
</ins></p></div><div class="section" id="default-language"><h3><span class="secno"><ins class="diff-new">
4.4
</ins></span>
Default
Language
</h3>
<p>
JSON-LD
allows
a
default
value
to
use
as
the
language
for
<a href="#dfn-string_value" title="string_value" class="tref internalDFN">
string
value
</a>
s.
It
is
commonly
the
case
that
documents
are
written
using
a
single
language.
As
described
in
<a href="string-internationalization">
String
Internationalization
</a>,
a
language-tagged
value
<em title="may" class="rfc2119">
may
</em>
be
specified
as
follows:
</p>
<del class="diff-old">{
...
  &quot;name&quot;:
  {
    &quot;@value&quot;: &quot;花澄&quot;,
    &quot;@language&quot;: &quot;ja&quot;
  }
...
</del>
<pre class="example">{
<ins class="diff-chg">  ...
  "name":
</ins>  <span class="diff">{
<ins class="diff-chg">
    "@value": "花澄",
    "@language": "ja"
  }</span>
</ins>
}
</pre>
<p>
It
is
also
possible
to
apply
a
particular
language
code
to
all
<a href="#dfn-string_value" title="string_value" class="tref internalDFN">
string
value
</a>
s
by
setting
the
<code>
@language
</code>
key
in
the
<code>
@context
</code>:
</p>
<del class="diff-old">{
  &quot;@context:&quot;
  {
    &quot;@language&quot;: &quot;ja&quot;
  },
...
  &quot;name&quot;:
  &quot;occupation&quot;:
...
</del>
<pre class="example">{
  <span class="diff">"@context":
<ins class="diff-chg">  {
    ...
    "@language": "ja"
  },</span>
  "name": <span class="diff">"花澄"</span>,
  "occupation": <span class="diff">"科学者"</span>
</ins>
}
</pre>
<p>
The
example
above
would
generate
a
<a href="#dfn-string_value" title="string_value" class="tref internalDFN">
string
value
</a>
for
<em>
花澄
</em>
and
<em>
科学者
</em>
and
associate
the
<code>
ja
</code>
language
code
with
each
value.
</p>
<p>
It
is
possible
to
override
the
default
language
by
using
the
expanded
form
of
a
value:
</p>
<del class="diff-old">{
  &quot;@context:&quot;
  {
     &quot;@language&quot;: &quot;ja&quot;
  },
...
  &quot;name&quot;: &quot;花澄&quot;
  &quot;occupation&quot;:
  {
    &quot;@value&quot;: &quot;Scientist&quot;,
    &quot;@language&quot;: &quot;en&quot;
  }
...
</del>
<pre class="example">{
<ins class="diff-chg">  "@context":
  {
    ...
    "@language": "ja"
  },
  "name": "花澄",
  "occupation":
</ins>  <span class="diff">{
<ins class="diff-chg">
    "@value": "Scientist",
    "@language": "en"
  }</span>
</ins>
}
</pre>
<p>
It
is
also
possible
to
override
the
default
language
and
specify
a
plain
value
by
omitting
the
<code>
@language
</code>
tag
when
expressing
the
expanded
value:
</p>
<del class="diff-old">{
  &quot;@context:&quot;
  {
     &quot;@language&quot;: &quot;ja&quot;
  },
...
  &quot;name&quot;: &quot;花澄&quot;
  &quot;occupation&quot;:
  {
    &quot;@value&quot;: &quot;Ninja&quot;
  }
...
</del>
<pre class="example">{
<ins class="diff-chg">  "@context":
  {
    ...
    "@language": "ja"
  },
  "name": "花澄",
  "occupation": <span class="diff">
  {
    "@value": "Ninja"
  }</span>
</ins>
}
</pre>
<p>
Object
<a href="#dfn-property" title="property" class="tref internalDFN">
properties
</a>
that
use
the
expanded
form
are
considered
explicitly
defined.
The
<code>
@language
</code>
keyword,
when
used
in
the
<a href="#dfn-context" title="context" class="tref internalDFN">
context
</a>,
<em title="must" class="rfc2119">
must
</em>
only
be
applied
to
<a href="#dfn-string_value" title="string_value" class="tref internalDFN">
string
value
</a>
s.
That
is,
<a href="#dfn-string_value" title="string_value" class="tref internalDFN">
string
value
</a>
s
expressed
in
expanded
form
are
not
affected
by
the
<code>
@language
</code>
keyword,
when
it
is
used
in
the
<a href="#dfn-context" title="context" class="tref internalDFN">
context
</a>.
</p>
<p>
<ins class="diff-new">To
clear
the
default
language
for
a
subtree,
</ins><code><ins class="diff-new">
@language
</ins></code><ins class="diff-new">
can
be
set
to
</ins><code><ins class="diff-new">
null
</ins></code><ins class="diff-new">
in
a
</ins><a href="#dfn-local_context" title="local_context" class="tref internalDFN"><ins class="diff-new">
local
context
</ins></a><ins class="diff-new">
as
follows:
</ins></p><pre class="example">{
<ins class="diff-new">
  "@context":
  {
    ...
    "@language": "ja"
  },
  "name": "花澄",
  "details":
  {
</ins><span class="diff">    "@context":
<ins class="diff-new">
    {
      "@language": null
    },</span>
    "occupation": "Ninja"
  }
}
</ins></pre>
</div>
<div class="section" id="expanded-term-definition">
<h3>
<span class="secno">
<del class="diff-old">4.4
</del>
<ins class="diff-chg">4.5
</ins>
</span>
Expanded
Term
Definition
</h3>
<p>
Within
a
<a href="#dfn-context" title="context" class="tref internalDFN">
context
</a>
definition,
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>
s
<em title="may" class="rfc2119">
may
</em>
be
defined
using
an
expanded
notation
to
allow
for
additional
information
associated
with
the
term
to
be
specified
(see
<a href="#type-coerceion">
Type
Coercion
</a>
and
<a href="#lists">
Lists
</a>
).
</p>
<p>
Instead
of
using
a
string
representation
of
an
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>,
the
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
<em title="may" class="rfc2119">
may
</em>
be
specified
using
an
object
having
an
<code>
@id
</code>
key.
The
value
of
the
<code>
@id
</code>
key
<em title="must" class="rfc2119">
must
</em>
be
either
a
<a href="#dfn-prefix" title="prefix" class="tref internalDFN">
prefix
</a>:suffix
value,
an
<a href="#dfn-iri" title="iri" class="tref internalDFN">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>.
Type
information
may
be
specified
</p>
<del class="diff-old">{
  &quot;@context&quot;: {
    &quot;foaf&quot;: ,
    &quot;name&quot;: ,
    &quot;homepage&quot;: ,
    &quot;depiction&quot;:
  },
  &quot;name&quot;: &quot;Manu Sporny&quot;,
  &quot;homepage&quot;: &quot;http://manu.sporny.org/&quot;,
  &quot;depiction&quot;: &quot;http://twitter.com/account/profile_image/manusporny&quot;
</del>
<pre class="example">{
<ins class="diff-chg">  "@context":
  {
    "foaf": <span class="diff">{ "@id": "http://xmlns.com/foaf/0.1/" }</span>,
    "name": <span class="diff">{ "@id": "http://xmlns.com/foaf/0.1/name" }</span>,
    "homepage": <span class="diff">{ "@id": "foaf:homepage" }</span>,
    "depiction": <span class="diff">{ "@id": "foaf:depiction" }</span>
  },
  "name": "Manu Sporny",
  "homepage": "http://manu.sporny.org/",
  "depiction": "http://twitter.com/account/profile_image/manusporny"
</ins>
}
</pre>
</div>
<div class="section" id="automatic-typing">
<h3>
<span class="secno">
<del class="diff-old">4.5
</del>
<ins class="diff-chg">4.6
</ins>
</span>
Automatic
Typing
</h3>
<p>
Since
JSON
is
capable
of
expressing
typed
information
such
as
doubles,
integers,
and
boolean
values.
As
demonstrated
below,
JSON-LD
utilizes
that
information
to
create
<a href="#dfn-typed_value" title="typed_value" class="tref internalDFN">
typed
value
</a>
s:
</p>
<del class="diff-old">{
...
  // The following two values are automatically converted to a type of xsd:double
  // and both values are equivalent to each other.
  &quot;measure:cups&quot;: ,
  &quot;measure:cups&quot;: ,
  // The following value is automatically converted to a type of xsd:double as well
  &quot;space:astronomicUnits&quot;: ,
  // The following value is never converted to a language-native type
  &quot;measure:stones&quot;: ,
  // This value is automatically converted to having a type of xsd:integer
  &quot;chem:protons&quot;: ,
  // This value is automatically converted to having a type of xsd:boolean
  &quot;sensor:active&quot;: ,
...
</del>
<pre class="example">{
<ins class="diff-chg">...
  // The following two values are automatically converted to a type of xsd:double
  // and both values are equivalent to each other.
  "measure:cups": <span class="diff">5.3</span>,
  "measure:cups": <span class="diff">5.3e0</span>,
  // The following value is automatically converted to a type of xsd:double as well
  "space:astronomicUnits": <span class="diff">6.5e73</span>,
  // The following value is never converted to a language-native type
  "measure:stones": <span class="diff">{ "@value": "4.8", "@type": "xsd:decimal" }</span>,
  // This value is automatically converted to having a type of xsd:integer
  "chem:protons": <span class="diff">12</span>,
  // This value is automatically converted to having a type of xsd:boolean
  "sensor:active": <span class="diff">true</span>,
...
</ins>
}
</pre>
<p class="note">
When
dealing
with
a
number
of
modern
programming
languages,
including
JavaScript
ECMA-262,
there
is
no
distinction
between
<strong>
xsd:decimal
</strong>
and
<strong>
xsd:double
</strong>
values.
That
is,
the
<a href="#dfn-number" title="number" class="tref internalDFN">
number
</a>
<code>
5.3
</code>
and
the
<a href="#dfn-number" title="number" class="tref internalDFN">
number
</a>
<code>
5.3e0
</code>
are
treated
as
if
they
were
the
same.
When
converting
from
JSON-LD
to
a
language-native
format
and
back,
type
information
is
lost
in
a
number
of
these
languages.
Thus,
one
could
say
that
<code>
5.3
</code>
is
a
<strong>
xsd:decimal
</strong>
and
<code>
5.3e0
</code>
is
an
<strong>
xsd:double
</strong>
in
JSON-LD,
but
when
both
values
are
converted
to
a
language-native
format
the
type
difference
between
the
two
is
lost
because
the
machine-level
representation
will
almost
always
be
a
<strong>
double
</strong>.
Implementers
should
be
aware
of
this
potential
round-tripping
issue
between
<strong>
xsd:decimal
</strong>
and
<strong>
xsd:double
</strong>.
Specifically
objects
with
a
type
of
<strong>
xsd:decimal
</strong>
<em title="must not" class="rfc2119">
must
not
</em>
be
converted
to
a
language
native
type.
</p>
</div>
<div class="section" id="type-coercion">
<h3>
<span class="secno">
<del class="diff-old">4.6
</del>
<ins class="diff-chg">4.7
</ins>
</span>
Type
Coercion
</h3>
<p>
JSON-LD
supports
the
coercion
of
values
to
particular
data
types.
Type
<dfn id="dfn-coercion" title="coercion">
coercion
</dfn>
allows
someone
deploying
JSON-LD
to
coerce
the
incoming
or
outgoing
types
to
the
proper
data
type
based
on
a
mapping
of
data
type
<a href="#dfn-iri" title="iri" class="tref internalDFN">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
s
to
property
types.
Using
type
coercion,
value
representation
is
preserved
without
requiring
the
data
type
to
be
specified
with
each
usage.
</p>
<p>
Type
coercion
is
specified
within
an
<a href="#expanded-term-definition">
expanded
term
definition
</a>
using
the
<code>
@type
</code>
key.
The
values
of
this
key
represent
type
IRIs
and
<em title="must" class="rfc2119">
must
</em>
take
the
form
of
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>,
<del class="diff-old">prefix
:suffix,
</del>
<a href="#dfn-compact_iri" title="compact_iri" class="tref internalDFN">
<ins class="diff-chg">compact
</ins><abbr title="Internationalized Resource Identifier"><ins class="diff-chg">
IRI
</ins></abbr></a>,<a href="#dfn-absolute_iri" title="absolute_iri" class="tref internalDFN">
absolute
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
or
the
keyword
<code>
@id
</code>.
Specifying
<code>
@id
</code>
indicates
that
within
the
body
of
a
JSON-LD
document,
string
values
of
keys
coerced
as
<code>
@id
</code>
are
to
be
interpreted
as
<a href="#dfn-iri" title="iri" class="tref internalDFN">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
s.
</p>
<p>
<a href="#dfn-term" title="term" class="tref internalDFN">
Terms
</a>
or
<del class="diff-old">prefixes
</del>
<a href="#dfn-compact_iri" title="compact_iri" class="tref internalDFN">
<ins class="diff-chg">compact
IRIs
</ins>
</a>
used
as
the
value
of
a
<code>
@type
</code>
key
<em title="may" class="rfc2119">
may
</em>
be
defined
within
the
same
context.
</p>
<p>
The
example
below
demonstrates
how
a
JSON-LD
author
can
coerce
values
to
<a href="#dfn-typed_value" title="typed_value" class="tref internalDFN">
typed
value
</a>
s,
IRIs
and
lists.
</p>
<del class="diff-old">{
  &quot;@context&quot;:
  {
     &quot;xsd&quot;: &quot;http://www.w3.org/2001/XMLSchema#&quot;,
     &quot;name&quot;: &quot;http://xmlns.com/foaf/0.1/name&quot;,
     &quot;age&quot;: ,
     &quot;homepage&quot;:
  },
  &quot;name&quot;: &quot;John Smith&quot;,
  &quot;age&quot;: ,
  &quot;homepage&quot;:
</del>
<pre class="example">{
<ins class="diff-chg">  "@context":
  {
    "xsd": "http://www.w3.org/2001/XMLSchema#",
    "name": "http://xmlns.com/foaf/0.1/name",
    "age":
</ins>    <span class="diff">{
<ins class="diff-chg">
      "@id": "http://xmlns.com/foaf/0.1/age",
      "@type": "xsd:integer"
    }</span>,
    "homepage":
</ins>    <span class="diff">{
<ins class="diff-chg">
      "@id": "http://xmlns.com/foaf/0.1/homepage",
      "@type": "@id",
      "@container": "@list"
    }</span>
  },
  "name": "John Smith",
  "age": <span class="diff">"41"</span>,
  "homepage":
</ins>  <span class="diff">[
<ins class="diff-chg">
    "http://personal.example.org/",
    "http://work.example.com/jsmith/"
  ]</span>
</ins>
}
</pre>
<p>
The
example
above
would
generate
the
following
Turtle:
</p>
<del class="diff-old">@prefix xsd: &lt;http://www.w3.org/2001/XMLSchema#&gt; .
[ foaf:name &quot;John Smith&quot;;
  foaf:age  &quot;41&quot;^^xsd:integer;
  foaf:homepage ( &lt;http://personal.example.org/&gt; &lt;http://work.example.com/jsmith/&gt; )
</del>
<pre class="example">@prefix xsd: &lt;http://www.w3.org/2001/XMLSchema#&gt; .
<ins class="diff-chg">
[ foaf:name "John Smith";
  foaf:age  "41"^^xsd:integer;
  foaf:homepage ( &lt;http://personal.example.org/&gt; &lt;http://work.example.com/jsmith/&gt; )
</ins>
]
.
</pre>
<p>
<ins class="diff-new">Terms
may
also
be
defined
using
</ins><a href="#dfn-absolute_iri" title="absolute_iri" class="tref internalDFN"><ins class="diff-new">
absolute
IRIs
</ins></a><ins class="diff-new">
or
</ins><a href="#dfn-compact_iri" title="compact_iri" class="tref internalDFN"><ins class="diff-new">
compact
IRIs
</ins></a>.<ins class="diff-new">
This
allows
coercion
rules
to
by
applied
to
keys
which
are
not
represented
as
a
simple
</ins><a href="#dfn-term" title="term" class="tref internalDFN"><ins class="diff-new">
term
</ins></a>.<ins class="diff-new">
For
example:
</ins></p><pre class="example">{
<ins class="diff-new">
  "@context":
  {
</ins>    <span class="diff">"foaf": "http://xmlns.com/foaf/0.1/"</span>,
<ins class="diff-new">
    "<span class="diff">foaf:age</span>":
    {
      "@id": "http://xmlns.com/foaf/0.1/"",
      "@type": "xsd:integer"
    },
    "<span class="diff">foaf:homepage</span>":
</ins>    <span class="diff">{
<ins class="diff-new">
      "@type": "@id"
    }</span>
}
</ins></pre><p><ins class="diff-new">
In
this
case,
the
</ins><code><ins class="diff-new">
@id
</ins></code><ins class="diff-new">
definition
is
optional,
but
if
it
does
exist,
the
</ins><a href="#dfn-compact_iri" title="compact_iri" class="tref internalDFN"><ins class="diff-new">
compact
</ins><abbr title="Internationalized Resource Identifier"><ins class="diff-new">
IRI
</ins></abbr></a><ins class="diff-new">
or
</ins><a href="#dfn-iri" title="iri" class="tref internalDFN"><abbr title="Internationalized Resource Identifier"><ins class="diff-new">
IRI
</ins></abbr></a><ins class="diff-new">
is
treated
as
a
term
so
that
the
actual
definition
of
a
</ins><a href="#dfn-prefix" title="prefix" class="tref internalDFN"><ins class="diff-new">
prefix
</ins></a><ins class="diff-new">
becomes
unnecessary.
</ins></p>
</div>
<div class="section" id="iri-expansion-within-a-context">
<h3>
<span class="secno">
<del class="diff-old">4.7
</del>
<ins class="diff-chg">4.8
</ins>
</span>
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
Expansion
Within
a
Context
</h3>
<p>
To
be
consistent
with
JSON-LD,
in
general,
anywhere
an
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
is
expected,
normal
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
expansion
rules
apply
(see
<a href="#iris">
IRIs
</a>
).
Within
a
<a href="#dfn-context" title="context" class="tref internalDFN">
context
</a>
definition,
this
can
mean
that
terms
defined
within
a
given
context
<em title="may" class="rfc2119">
may
</em>
also
be
used
within
that
context,
as
long
as
there
are
no
circular
dependencies.
For
example,
it
is
common
to
use
the
<code>
xsd
</code>
namespace
when
defining
<a href="#dfn-typed_value" title="typed_value" class="tref internalDFN">
typed
value
</a>
s:
</p>
<del class="diff-old">{
  &quot;@context&quot;: {
    ,
    &quot;name&quot;: &quot;http://xmlns.com/foaf/0.1/name&quot;,
    &quot;age&quot;: {&quot;@id&quot;: &quot;http://xmlns.com/foaf/0.1/age&quot;, &quot;@type&quot;: },
    &quot;homepage&quot;: {&quot;@id&quot;: &quot;http://xmlns.com/foaf/0.1/homepage&quot;, &quot;@type&quot;: &quot;@id&quot;}
  },
  ...
</del>
<pre class="example">{
<ins class="diff-chg">  "@context":
  {
</ins>    <span class="diff">"xsd": "http://www.w3.org/2001/XMLSchema#"</span>,
<ins class="diff-chg">
    "name": "http://xmlns.com/foaf/0.1/name",
    "age":
    {
      "@id": "http://xmlns.com/foaf/0.1/age",
      "@type": <span class="diff">"xsd:integer"</span>
    },
    "homepage":
    {
      "@id": "http://xmlns.com/foaf/0.1/homepage",
      "@type": "@id"
    }
  },
  ...
</ins>
}
</pre>
<p>
In
this
example,
the
<code>
xsd
</code>
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>
is
defined,
and
used
as
a
<a href="#dfn-prefix" title="prefix" class="tref internalDFN">
prefix
</a>
for
the
<code>
@type
</code>
coercion
of
the
<code>
age
</code>
property.
</p>
<p>
<a href="#dfn-term" title="term" class="tref internalDFN">
Term
</a>
s
<em title="may" class="rfc2119">
may
</em>
also
be
used
when
defining
the
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
of
another
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>:
</p>
<del class="diff-old">{
  &quot;@context&quot;:
  {
    ,
    &quot;xsd&quot;: &quot;http://www.w3.org/2001/XMLSchema#&quot;,
    &quot;name&quot;: ,
    &quot;age&quot;: {&quot;@id&quot;: , &quot;@type&quot;: xsd:integer&quot;},
    &quot;homepage&quot;: {&quot;@id&quot;: , &quot;@type&quot;: &quot;@id&quot;}
  },
  ...
</del>
<pre class="example">{
<ins class="diff-chg">  "@context":
  {
</ins>    <span class="diff">"foaf": "http://xmlns.com/foaf/0.1/"</span>,
<ins class="diff-chg">
    "xsd": "http://www.w3.org/2001/XMLSchema#",
    "name": <span class="diff">"foaf:name"</span>,
    "age":
    {
      "@id": <span class="diff">"foaf:age"</span>,
      "@type": "xsd:integer"
    },
    "homepage":
    {
      "@id": <span class="diff">"foaf:homepage"</span>,
      "@type": "@id"
    }
  },
  ...
</ins>
}
</pre>
<p>
<a href="#dfn-term" title="term" class="tref internalDFN">
Term
</a>
s
<em title="may" class="rfc2119">
may
</em>
also
be
used
on
the
left-hand
side
of
a
definition.
</p>
<del class="diff-old">{
  &quot;@context&quot;:
  {
    ,
    &quot;xsd&quot;: &quot;http://www.w3.org/2001/XMLSchema#&quot;,
    &quot;name&quot;: &quot;foaf:name&quot;,
    &quot;&quot;: {&quot;@id&quot;: &quot;foaf:age&quot;, &quot;@type&quot;: xsd:integer&quot;},
    &quot;
  },
  ...
</del>
<pre class="example">{
<ins class="diff-chg">  "@context":
  {
</ins>    <span class="diff">"foaf": "http://xmlns.com/foaf/0.1/"</span>,
<ins class="diff-chg">
    "xsd": "http://www.w3.org/2001/XMLSchema#",
    "name": "foaf:name",
    "<span class="diff">foaf:age</span>":
    {
      "@id": "foaf:age",
      "@type": "xsd:integer"
    },
    "<span class="diff">foaf:homepage</span>":
</ins>    <span class="diff">{
<ins class="diff-chg">
      "@type": "@id"
    }</span>
  },
  ...
</ins>
}
</pre>
<p>
Note
that
in
this
example,
the
<del class="diff-old">prefixed
</del>
<a href="#dfn-compact_iri" title="compact_iri" class="tref internalDFN">
<ins class="diff-chg">compact
</ins><abbr title="Internationalized Resource Identifier"><ins class="diff-chg">
IRI
</ins></abbr></a>
form
is
used
in
two
different
ways.
The
first
way,
as
shown
with
<code>
foaf:age
</code>
declares
both
the
<a href="#dfn-iri" title="iri" class="tref internalDFN">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
for
the
term
(using
short-form)
as
well
as
the
<code>
@type
</code>
associated
with
the
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>.
The
second
way,
only
declares
the
<code>
@type
</code>
associated
with
the
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>.
In
the
second
case,
the
JSON-LD
processor
will
still
derive
the
full
<a href="#dfn-iri" title="iri" class="tref internalDFN">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
by
looking
up
the
<code>
foaf
</code>
<a href="#dfn-prefix" title="prefix" class="tref internalDFN">
prefix
</a>
in
the
<a href="#dfn-context" title="context" class="tref internalDFN">
context
</a>
for
<code>
foaf:homepage
</code>.
</p>
<p>
Full
IRIs
<em title="may" class="rfc2119">
may
</em>
also
be
used
on
the
left-hand
side
of
a
<a href="#dfn-context" title="context" class="tref internalDFN">
context
</a>:
</p>
<del class="diff-old">{
  &quot;@context&quot;:
  {
    &quot;foaf&quot;: &quot;http://xmlns.com/foaf/0.1/&quot;,
    &quot;xsd&quot;: &quot;http://www.w3.org/2001/XMLSchema#&quot;,
    &quot;name&quot;: &quot;foaf:name&quot;,
    &quot;foaf:age&quot;: {&quot;@id&quot;: &quot;foaf:age&quot;, &quot;@type&quot;: xsd:integer&quot;},
    &quot;&quot;: { &quot;@type&quot;: &quot;@id&quot; }
  },
  ...
</del>
<pre class="example">{
<ins class="diff-chg">  "@context":
  {
    "foaf": "http://xmlns.com/foaf/0.1/",
    "xsd": "http://www.w3.org/2001/XMLSchema#",
    "name": "foaf:name",
    "foaf:age":
    {
      "@id": "foaf:age",
      "@type": "xsd:integer"
    },
    "<span class="diff">http://xmlns.com/foaf/0.1/homepage</span>":
    {
      "@type": "@id"
    }
  },
  ...
</ins>
}
</pre>
<p>
Note
that
in
order
for
the
full
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
to
match
above,
the
full
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
<em title="must" class="rfc2119">
must
</em>
also
be
used
in
the
JSON-LD
document.
Also
note
that
<code>
foaf:homepage
</code>
will
not
use
the
<code>
{
<del class="diff-old">&quot;@type&quot;:
&quot;@id&quot;
</del>
<ins class="diff-chg">"@type":
"@id"
</ins>
}
</code>
declaration
because
<code>
foaf:homepage
</code>
is
not
the
same
as
<code>
http://xmlns.com/foaf/0.1/homepage
</code>.
That
is,
a
JSON-LD
processor
will
use
direct
string
comparison
when
looking
up
<a href="#dfn-term" title="term" class="tref internalDFN">
term
</a>
s
in
a
<a href="#dfn-context" title="context" class="tref internalDFN">
context
</a>
before
it
applies
the
<a href="#dfn-prefix" title="prefix" class="tref internalDFN">
prefix
</a>
lookup
mechanism.
</p>
<p>
The
only
exception
for
using
terms
in
the
<a href="#dfn-context" title="context" class="tref internalDFN">
context
</a>
is
that
they
<em title="must not" class="rfc2119">
must
not
</em>
be
used
in
a
circular
manner.
That
is,
a
definition
of
<em>
term-1
</em>
<em title="must not" class="rfc2119">
must
not
</em>
depend
on
the
definition
of
<em>
term-2
</em>
if
<em>
term-2
</em>
also
depends
on
<em>
term-1
</em>.
For
example,
the
following
<a href="#dfn-context" title="context" class="tref internalDFN">
context
</a>
definition
is
illegal:
</p>
<del class="diff-old">{
  &quot;@context&quot;:
  {
    &quot;term1&quot;: {&quot;@id&quot;: &quot;term2:foo&quot;},
    &quot;term2&quot;: {&quot;@id&quot;: &quot;term1:bar&quot;}
  },
  ...
</del>
<pre class="example">{
<ins class="diff-chg">  "@context":
  {
</ins>    <span class="diff">"term1": "term2:foo",
<ins class="diff-chg">
    "term2": "term1:bar"</span>
  },
  ...
</ins>
}
</pre>
</div>
<div class="section" id="embedding">
<h3>
<span class="secno">
<del class="diff-old">4.8
</del>
<ins class="diff-chg">4.9
</ins>
</span>
Embedding
</h3>
<p>
Object
<dfn id="dfn-embedding" title="embedding">
embedding
</dfn>
is
a
JSON-LD
feature
that
allows
an
author
to
use
the
definition
of
JSON-LD
objects
as
<a href="#dfn-property" title="property" class="tref internalDFN">
property
</a>
values.
This
is
a
commonly
used
mechanism
for
creating
a
parent-child
relationship
between
two
<a href="#dfn-subject" title="subject" class="tref internalDFN">
subject
</a>
s.
</p>
<p>
The
example
shows
<del class="diff-old">an
</del>
two
subjects
related
by
a
property
from
the
first
subject:
</p>
<del class="diff-old">  {
...
  &quot;name&quot;: &quot;Manu Sporny&quot;,
  &quot;&quot;: {
    &quot;&quot;,
    &quot;&quot;,
  }
...
</del>
  <pre class="example">{
<ins class="diff-chg">...
  "name": "Manu Sporny",
  "<span class="diff">knows</span>":
  {
    "<span class="diff">@type</span>": "<span class="diff">Person</span>",
    "<span class="diff">name</span>": "<span class="diff">Gregg Kellogg</span>",
  }
...
</ins>
}
</pre>
<p>
An
object
definition,
like
the
one
used
above,
<em title="may" class="rfc2119">
may
</em>
be
used
as
a
JSON
value
at
any
point
in
JSON-LD.
</p>
</div>
<div class="section" id="identifying-unlabeled-nodes">
<h3>
<span class="secno">
<del class="diff-old">4.9
</del>
<ins class="diff-chg">4.10
</ins>
</span>
Identifying
Unlabeled
Nodes
</h3>
<p>
At
times,
it
becomes
necessary
to
be
able
to
express
information
without
being
able
to
specify
the
subject.
Typically,
this
type
of
node
is
called
an
unlabeled
node
or
a
blank
node.
In
JSON-LD,
unlabeled
node
identifiers
are
automatically
created
if
a
subject
is
not
specified
using
the
<code>
@id
</code>
keyword.
However,
authors
may
provide
identifiers
for
unlabeled
nodes
by
using
the
special
<code>
_
</code>
(underscore)
<a href="#dfn-prefix" title="prefix" class="tref internalDFN">
prefix
</a>.
This
allows
to
reference
the
node
locally
within
the
document
but
not
in
an
external
document.
</p>
<del class="diff-old">{
...
  &quot;@id&quot;: &quot;&quot;,
...
</del>
<pre class="example">{
<ins class="diff-chg">...
  "@id": "<span class="diff">_:foo</span>",
...
</ins>
}
</pre>
<p>
The
example
above
would
set
the
subject
to
<code>
_:foo
</code>,
which
can
then
be
used
later
on
in
the
JSON-LD
markup
to
refer
back
to
the
unlabeled
node.
This
practice,
however,
is
usually
frowned
upon
when
generating
<a href="#dfn-linked_data" title="linked_data" class="tref internalDFN">
Linked
Data
</a>.
If
a
developer
finds
that
they
refer
to
the
unlabeled
node
more
than
once,
they
should
consider
naming
the
node
using
a
resolve-able
<a href="#dfn-iri" title="iri" class="tref internalDFN">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>.
</p>
</div>
<div class="section" id="aliasing-keywords">
<h3>
<span class="secno">
<del class="diff-old">4.10
</del>
<ins class="diff-chg">4.11
</ins>
</span>
Aliasing
Keywords
</h3>
<p>
JSON-LD
allows
all
of
the
syntax
keywords,
except
for
<code>
@context
</code>,
to
be
aliased.
This
feature
allows
more
legacy
JSON
content
to
be
supported
by
JSON-LD.
It
also
allows
developers
to
design
domain-specific
implementations
using
only
the
JSON-LD
<a href="#dfn-context" title="context" class="tref internalDFN">
context
</a>.
</p>
<del class="diff-old">{
  &quot;@context&quot;:
  {
     ,
     ,
     &quot;name&quot;: &quot;http://schema.org/name&quot;
  },
  &quot;url&quot;: &quot;http://example.com/about#gregg&quot;,
  &quot;a&quot;: &quot;http://schema.org/Person&quot;,
  &quot;name&quot;: &quot;Gregg Kellogg&quot;
</del>
<pre class="example">{
<ins class="diff-chg">  "@context":
  {
</ins>     <span class="diff">"url": "@id"</span>,
     <span class="diff">"a": "@type"</span>,
<ins class="diff-chg">
     "name": "http://schema.org/name"
  },
  "url": "http://example.com/about#gregg",
  "a": "http://schema.org/Person",
  "name": "Gregg Kellogg"
</ins>
}
</pre>
<p>
In
the
example
above,
the
<code>
@id
</code>
and
<code>
@type
</code>
keywords
have
been
given
the
aliases
<strong>
url
</strong>
and
<strong>
a
</strong>,
respectively.
</p>
</div>
<div class="section" id="expansion">
<h3>
<span class="secno">
<ins class="diff-new">4.12
</ins></span><ins class="diff-new">
Expansion
</ins></h3><p><ins class="diff-new">
The
JSON-LD
API
[
</ins><cite><a href="#bib-JSON-LD-API" rel="biblioentry" class="bibref"><ins class="diff-new">
JSON-LD-API
</ins></a></cite><ins class="diff-new">
]
defines
an
method
for
</ins><em><ins class="diff-new">
expanding
</ins></em><ins class="diff-new">
a
JSON-LD
document.
Expansion
is
the
process
of
taking
a
JSON-LD
document
and
applying
a
context
such
that
all
</ins><abbr title="Internationalized Resource Identifier"><ins class="diff-new">
IRI
</ins></abbr>,<ins class="diff-new">
datatypes,
and
literal
values
are
expanded
so
that
the
context
is
no
longer
necessary.
JSON-LD
document
expansion
is
typically
used
as
a
part
of
</ins><a href="#framing"><ins class="diff-new">
Framing
</ins></a>.</p><p><ins class="diff-new">
For
example,
assume
the
following
JSON-LD
input
document:
</ins></p><pre class="example">{
<ins class="diff-new">
   "@context":
   {
      "name": "http://xmlns.com/foaf/0.1/name",
      "homepage": {
        "@id": "http://xmlns.com/foaf/0.1/homepage",
        "@type", "@id"
      }
   },
   "name": "Manu Sporny",
   "homepage": "http://manu.sporny.org/"
}
</ins></pre><p><ins class="diff-new">
Running
the
JSON-LD
Expansion
algorithm
against
the
JSON-LD
input
document
provided
above
would
result
in
the
following
output:
</ins></p><pre class="example">{
<ins class="diff-new">
   "http://xmlns.com/foaf/0.1/name": "Manu Sporny",
   "http://xmlns.com/foaf/0.1/homepage": {
      "@id": "http://manu.sporny.org/"
   }
}
</ins></pre>
</div>
<div class="section" id="compaction">
<h3>
<span class="secno">
<ins class="diff-chg">4.13
</ins></span><ins class="diff-chg">
Compaction
</ins></h3><p><ins class="diff-chg">
The
JSON-LD
API
[
</ins><cite><a href="#bib-JSON-LD-API" rel="biblioentry" class="bibref"><ins class="diff-chg">
JSON-LD-API
</ins></a></cite><ins class="diff-chg">
]
defines
an
method
for
</ins><em><ins class="diff-chg">
compacting
</ins></em><ins class="diff-chg">
a
JSON-LD
document.
Compaction
is
the
process
of
taking
a
JSON-LD
document
and
applying
a
context
such
that
the
most
compact
form
of
the
document
is
generated.
JSON
is
typically
expressed
in
a
very
compact,
key-value
format.
That
is,
full
IRIs
are
rarely
used
as
keys.
At
times,
a
JSON-LD
document
may
be
received
that
is
not
in
its
most
compact
form.
JSON-LD,
via
the
API,
provides
a
way
to
compact
a
JSON-LD
document.
</ins></p><p><ins class="diff-chg">
For
example,
assume
the
following
JSON-LD
input
document:
</ins></p><pre class="example">{
<ins class="diff-chg">
  "http://xmlns.com/foaf/0.1/name": "Manu Sporny",
  "http://xmlns.com/foaf/0.1/homepage": {
    "@id": "http://manu.sporny.org/"
  }
}
</ins></pre><p><ins class="diff-chg">
Additionally,
assume
the
following
developer-supplied
JSON-LD
context:
</ins></p><pre class="example">{
<ins class="diff-chg">
  "name": "http://xmlns.com/foaf/0.1/name",
  "homepage": {
    "@id": "http://xmlns.com/foaf/0.1/homepage",
    "@type": "@id"
  }
}
</ins></pre><p><ins class="diff-chg">
Running
the
JSON-LD
Compaction
algorithm
given
the
context
supplied
above
against
the
JSON-LD
input
document
provided
above
would
result
in
the
following
output:
</ins></p><pre class="example">{
<ins class="diff-chg">
  "@context": {
    "name": "http://xmlns.com/foaf/0.1/name",
    "homepage": {
      "@id": "http://xmlns.com/foaf/0.1/homepage",
      "@type": "@id"
    }
  },
  "name": "Manu Sporny",
  "homepage": "http://manu.sporny.org/"
}
</ins></pre><p><ins class="diff-chg">
The
compaction
algorithm
also
enables
the
developer
to
map
any
expanded
format
into
an
application-specific
compacted
format.
While
the
context
provided
above
mapped
</ins><code><ins class="diff-chg">
http://xmlns.com/foaf/0.1/name
</ins></code><ins class="diff-chg">
to
</ins><strong><ins class="diff-chg">
name
</ins></strong>,<ins class="diff-chg">
it
could
have
also
mapped
it
to
any
arbitrary
string
provided
by
the
developer.
</ins></p></div><div class="section" id="framing"><h3><span class="secno"><ins class="diff-chg">
4.14
</ins></span><ins class="diff-chg">
Framing
</ins></h3><p><ins class="diff-chg">
The
JSON-LD
API
[
</ins><cite><a href="#bib-JSON-LD-API" rel="biblioentry" class="bibref"><ins class="diff-chg">
JSON-LD-API
</ins></a></cite><ins class="diff-chg">
]
defines
an
method
for
</ins><em><ins class="diff-chg">
framing
</ins></em><ins class="diff-chg">
a
JSON-LD
document.
This
allows
developers
to
query
by
example
and
force
a
specific
tree
layout
to
a
JSON-LD
document.
</ins></p><p><ins class="diff-chg">
A
JSON-LD
document
is
a
representation
of
a
directed
graph.
A
single
directed
graph
can
have
many
different
serializations,
each
expressing
exactly
the
same
information.
Developers
typically
work
with
trees,
represented
as
</ins><a href="#dfn-json_object" title="json_object" class="tref internalDFN"><ins class="diff-chg">
JSON
object
</ins></a><ins class="diff-chg">
s.
While
mapping
a
graph
to
a
tree
can
be
done,
the
layout
of
the
end
result
must
be
specified
in
advance.
A
</ins><dfn id="dfn-frame" title="frame"><ins class="diff-chg">
Frame
</ins></dfn><ins class="diff-chg">
can
be
used
by
a
developer
on
a
JSON-LD
document
to
specify
a
deterministic
layout
for
a
graph.
</ins></p><p><ins class="diff-chg">
Framing
is
the
process
of
taking
a
JSON-LD
document,
which
expresses
a
graph
of
information,
and
applying
a
specific
graph
layout
(called
a
</ins><a href="#dfn-frame" title="frame" class="tref internalDFN"><ins class="diff-chg">
Frame
</ins></a><ins class="diff-chg">
).
</ins></p><p><ins class="diff-chg">
The
JSON-LD
document
below
expresses
a
library,
a
book
and
a
chapter:
</ins></p><pre class="example">{
<ins class="diff-chg">
  "@context": {
    "Book":         "http://example.org/vocab#Book",
    "Chapter":      "http://example.org/vocab#Chapter",
    "contains":     {
      "@id": "http://example.org/vocab#contains",
      "@type": "@id"
    },
    "creator":      "http://purl.org/dc/terms/creator",
    "description":  "http://purl.org/dc/terms/description",
    "Library":      "http://example.org/vocab#Library",
    "title":        "http://purl.org/dc/terms/title"
  },
  "@id":
  [{
    "@id": "http://example.com/library",
    "@type": "Library",
    "contains": "http://example.org/library/the-republic"
  },
  {
    "@id": "http://example.org/library/the-republic",
    "@type": "Book",
    "creator": "Plato",
    "title": "The Republic",
    "contains": "http://example.org/library/the-republic#introduction"
  },
  {
    "@id": "http://example.org/library/the-republic#introduction",
    "@type": "Chapter",
    "description": "An introductory chapter on The Republic.",
    "title": "The Introduction"
  }]
}
</ins></pre><p><ins class="diff-chg">
Developers
typically
like
to
operate
on
items
in
a
hierarchical,
tree-based
fashion.
Ideally,
a
developer
would
want
the
data
above
sorted
into
top-level
libraries,
then
the
books
that
are
contained
in
each
library,
and
then
the
chapters
contained
in
each
book.
To
achieve
that
layout,
the
developer
can
define
the
following
</ins><a href="#dfn-frame" title="frame" class="tref internalDFN"><ins class="diff-chg">
frame
</ins></a>:</p><pre class="example">{
<ins class="diff-chg">
  "@context": {
    "Book":         "http://example.org/vocab#Book",
    "Chapter":      "http://example.org/vocab#Chapter",
    "contains":     "http://example.org/vocab#contains",
    "creator":      "http://purl.org/dc/terms/creator"
    "description":  "http://purl.org/dc/terms/description"
    "Library":      "http://example.org/vocab#Library",
    "title":        "http://purl.org/dc/terms/title"
  },
  "@type": "Library",
  "contains": {
    "@type": "Book",
    "contains": {
      "@type": "Chapter"
    }
  }
}
</ins></pre><p><ins class="diff-chg">
When
the
framing
algorithm
is
run
against
the
previously
defined
JSON-LD
document,
paired
with
the
</ins><a href="#dfn-frame" title="frame" class="tref internalDFN"><ins class="diff-chg">
frame
</ins></a><ins class="diff-chg">
above,
the
following
JSON-LD
document
is
the
end
result:
</ins></p><pre class="example">{
<ins class="diff-chg">
  "@context": {
    "Book":         "http://example.org/vocab#Book",
    "Chapter":      "http://example.org/vocab#Chapter",
    "contains":     "http://example.org/vocab#contains",
    "creator":      "http://purl.org/dc/terms/creator"
    "description":  "http://purl.org/dc/terms/description"
    "Library":      "http://example.org/vocab#Library",
    "title":        "http://purl.org/dc/terms/title"
  },
  "@id": "http://example.org/library",
  "@type": "Library",
  "contains": {
</ins>    <span class="diff">"@id": "http://example.org/library/the-republic",</span>
<ins class="diff-chg">
    "@type": "Book",
</ins>    <span class="diff">"creator": "Plato",</span>
    <span class="diff">"title": "The Republic",</span>
<ins class="diff-chg">
    "contains": {
</ins>      <span class="diff">"@id": "http://example.org/library/the-republic#introduction",</span>
<ins class="diff-chg">
      "@type": "Chapter",
</ins>      <span class="diff">"description": "An introductory chapter on The Republic.",</span>
      <span class="diff">"title": "The Introduction"</span>
<ins class="diff-chg">
    },
  },
}
</ins></pre></div><div class="section" id="normalization"><h3><span class="secno"><ins class="diff-chg">
4.15
</ins></span><ins class="diff-chg">
Normalization
</ins></h3><p><ins class="diff-chg">
The
JSON-LD
API
[
</ins><cite><a href="#bib-JSON-LD-API" rel="biblioentry" class="bibref"><ins class="diff-chg">
JSON-LD-API
</ins></a></cite><ins class="diff-chg">
]
defines
an
method
for
</ins><em><ins class="diff-chg">
normalizing
</ins></em><ins class="diff-chg">
a
JSON-LD
document.
Normalization
is
the
process
of
performing
a
deterministic
transformation
on
a
JSON-LD
document
resulting
in
a
normalized
representation.
</ins></p><p><ins class="diff-chg">
Normalization
is
useful
when
comparing
two
graphs
against
one
another,
when
generating
a
detailed
list
of
differences
between
two
graphs,
and
when
generating
a
cryptographic
digital
signature
for
information
contained
in
a
graph
or
when
generating
a
hash
of
the
information
contained
in
a
graph.
</ins></p><p><ins class="diff-chg">
The
example
below
is
an
un-normalized
JSON-LD
document:
</ins></p><pre class="example">{
<ins class="diff-chg">
  "@context": {
    "name": "http://xmlns.com/foaf/0.1/name",
    "homepage": {
      "@id": "http://xmlns.com/foaf/0.1/homepage",
      "@type": "@id"
    },
    "xsd": "http://www.w3.org/2001/XMLSchema#"
  },
  "name": "Manu Sporny",
  "homepage": "http://manu.sporny.org/"
}
</ins></pre><p><ins class="diff-chg">
The
example
below
is
the
normalized
form
of
the
JSON-LD
document
above:
</ins></p><pre class="example">[{
<ins class="diff-chg">
  "@id": "_:c14n0",
  "http://xmlns.com/foaf/0.1/homepage": {
    "@id": "http://manu.sporny.org/"
  },
  "http://xmlns.com/foaf/0.1/name": "Manu Sporny"
}]
</ins></pre><p><ins class="diff-chg">
Notice
how
all
of
the
</ins><a href="#dfn-term" title="term" class="tref internalDFN"><ins class="diff-chg">
term
</ins></a><ins class="diff-chg">
s
have
been
expanded
and
sorted
in
alphabetical
order.
Also,
notice
how
the
</ins><a href="#dfn-subject" title="subject" class="tref internalDFN"><ins class="diff-chg">
subject
</ins></a><ins class="diff-chg">
has
been
labeled
with
a
named
</ins><a href="#dfn-unlabeled_node" title="unlabeled_node" class="tref internalDFN"><ins class="diff-chg">
unlabeled
node
</ins></a>.<ins class="diff-chg">
Normalization
ensures
that
any
arbitrary
graph
containing
exactly
the
same
information
would
be
normalized
to
exactly
the
same
form
shown
above.
</ins></p></div></div><div id="markup-examples" class="appendix informative section">
<h2>
<span class="secno">
A.
</span>
Markup
Examples
</h2>
<p>
<em>
This
section
is
non-normative.
</em>
</p>
<p>
JSON-LD
is
a
specification
for
representing
<a href="#dfn-linked_data" title="linked_data" class="tref internalDFN">
Linked
Data
</a>
in
JSON.
A
common
way
of
working
with
Linked
Data
is
through
<dfn id="dfn-rdf" title="rdf">
RDF
</dfn>,
the
Resource
Description
Framework.
RDF
can
be
expressed
using
JSON-LD
by
associating
JSON-LD
concepts
such
as
<code>
@id
</code>
and
<code>
@type
</code>
with
the
equivalent
<a href="#dfn-iri" title="iri" class="tref internalDFN">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
s
in
RDF.
Further
information
about
RDF
may
be
found
in
[
<cite>
<a href="#bib-RDF-PRIMER" rel="biblioentry" class="bibref">
RDF-PRIMER
</a>
</cite>
].
</p>
<p>
The
JSON-LD
markup
examples
below
demonstrate
how
JSON-LD
can
be
used
to
express
semantic
data
marked
up
in
other
languages
such
as
Turtle,
RDFa,
Microformats,
and
Microdata.
These
sections
are
merely
provided
as
proof
that
JSON-LD
is
very
flexible
in
what
it
can
express
across
different
<a href="#dfn-linked_data" title="linked_data" class="tref internalDFN">
Linked
Data
</a>
approaches.
Details
of
transforming
JSON-LD
into
RDF
are
defined
in
[
<cite>
<a href="#bib-JSON-LD-API" rel="biblioentry" class="bibref">
JSON-LD-API
</a>
</cite>
].
</p>
<div class="section" id="turtle">
<h3>
<span class="secno">
A.1
</span>
Turtle
</h3>
<p>
The
following
are
examples
of
representing
<a href="#dfn-rdf" title="rdf" class="tref internalDFN">
RDF
</a>
as
expressed
in
[
<cite>
<a href="#bib-TURTLE" rel="biblioentry" class="bibref">
TURTLE
</a>
</cite>
]
into
JSON-LD.
</p>
<div class="section" id="prefix-definitions">
<h4>
<span class="secno">
A.1.1
</span>
Prefix
definitions
</h4>
<p>
The
JSON-LD
context
has
direct
equivalents
for
the
Turtle
<code>
@prefix
</code>
declaration:
</p>
<del class="diff-old">@prefix foaf: &lt;http://xmlns.com/foaf/0.1/&gt; .
&lt;http://manu.sporny.org/i/public&gt; a foaf:Person;
  foaf:name &quot;Manu Sporny&quot;;
</del>
<pre class="example">@prefix foaf: &lt;http://xmlns.com/foaf/0.1/&gt; .
<ins class="diff-chg">
&lt;http://manu.sporny.org/i/public&gt; a foaf:Person;
  foaf:name "Manu Sporny";
</ins>
foaf:homepage
&lt;http://manu.sporny.org/&gt;
.
</pre>
<del class="diff-old">{
  &quot;@context&quot;: {
    &quot;foaf&quot;:   &quot;http://xmlns.com/foaf/0.1/&quot;
  },
  &quot;@id&quot;:            &quot;http://manu.sporny.org/i/public&quot;,
  &quot;@type&quot;:          &quot;foaf:Person&quot;,
  &quot;foaf:name&quot;:      &quot;Manu Sporny&quot;,
  &quot;foaf:homepage&quot;:  { &quot;@id&quot;: &quot;http://manu.sporny.org/&quot; }
</del>
<pre class="example">{
<ins class="diff-chg">  "@context":
  {
    "foaf": "http://xmlns.com/foaf/0.1/"
  },
  "@id": "http://manu.sporny.org/i/public",
  "@type": "foaf:Person",
  "foaf:name": "Manu Sporny",
  "foaf:homepage": { "@id": "http://manu.sporny.org/" }
</ins>
}
</pre>
<div class="note">
<p>
JSON-LD
has
no
equivalent
for
the
Turtle
<code>
@base
</code>
declaration.
Authors
could,
of
course,
use
a
prefix
definition
to
resolve
<a href="#dfn-relative_iri" title="relative_iri" class="tref internalDFN">
relative
<del class="diff-old">IRIs.
</del>
<abbr title="Internationalized Resource Identifier">
<ins class="diff-chg">IRI
</ins></abbr></a><ins class="diff-chg">
s.
</ins>
For
example,
an
empty
prefix
could
be
used
to
get
a
similar
effect
to
<code>
@base
</code>:
</p>
<del class="diff-old">{
  &quot;@context&quot;: {

    &quot;foaf&quot;:   &quot;http://xmlns.com/foaf/0.1/&quot;
  },
  &quot;@id&quot;:            ,
  &quot;@type&quot;:          &quot;foaf:Person&quot;,
  &quot;foaf:name&quot;:      &quot;Manu Sporny&quot;,
  &quot;foaf:homepage&quot;:  { &quot;@id&quot;: }
</del>
<pre class="example">{
<ins class="diff-chg">  "@context":
  {
</ins>    <span class="diff">"": "http://manu.sporny.org/",</span>
<ins class="diff-chg">
    "foaf": "http://xmlns.com/foaf/0.1/"
  },
  "@id": <span class="diff">":i/public"</span>,
  "@type": "foaf:Person",
  "foaf:name": "Manu Sporny",
  "foaf:homepage": { "@id": <span class="diff">":" </span>}
</ins>
}
</pre>
</div>
</div>
<div class="section" id="embedding-1">
<h4>
<span class="secno">
A.1.2
</span>
Embedding
</h4>
<p>
Both
Turtle
and
JSON-LD
allow
embedding
of
objects,
although
Turtle
only
allows
embedding
of
objects
which
use
unlabeled
node
identifiers.
</p>
</div>
<del class="diff-old">@prefix foaf: &lt;http://xmlns.com/foaf/0.1/&gt; .
&lt;http://manu.sporny.org/i/public&gt;
  a foaf:Person;
  foaf:name &quot;Manu Sporny&quot;;
</del>
<pre class="example">@prefix foaf: &lt;http://xmlns.com/foaf/0.1/&gt; .
<ins class="diff-chg">
&lt;http://manu.sporny.org/i/public&gt;
  a foaf:Person;
  foaf:name "Manu Sporny";
</ins>
foaf:knows
[
a
foaf:Person;
foaf:name
<del class="diff-old">&quot;Gregg
Kellogg&quot;
</del>
<ins class="diff-chg">"Gregg
Kellogg"
</ins>
]
.
</pre>
<del class="diff-old">{
  &quot;@context&quot;: {
    &quot;foaf&quot;:   &quot;http://xmlns.com/foaf/0.1/&quot;
  },
  &quot;@id&quot;:            &quot;http://manu.sporny.org/i/public&quot;,
  &quot;@type&quot;:          &quot;foaf:Person&quot;,
  &quot;foaf:name&quot;:      &quot;Manu Sporny&quot;,
  &quot;foaf:knows&quot;: {
    &quot;@type&quot;:        &quot;foaf:Person&quot;,
    &quot;foaf:name&quot;:    &quot;Gregg Kellogg&quot;
  }
</del>
<pre class="example">{
<ins class="diff-chg">  "@context":
  {
    "foaf": "http://xmlns.com/foaf/0.1/"
  },
  "@id": "http://manu.sporny.org/i/public",
  "@type": "foaf:Person",
  "foaf:name": "Manu Sporny",
  "foaf:knows":
  {
    "@type": "foaf:Person",
    "foaf:name": "Gregg Kellogg"
  }
</ins>
}
</pre>
<div class="section" id="lists-1">
<h4>
<span class="secno">
A.1.3
</span>
Lists
</h4>
<p>
Both
JSON-LD
and
Turtle
can
represent
sequential
lists
of
values.
</p>
<del class="diff-old">@prefix foaf: &lt;http://xmlns.com/foaf/0.1/&gt; .
&lt;http://example.org/people#joebob&gt; a foaf:Person;
  foaf:name &quot;Joe Bob&quot;;
</del>
<pre class="example">@prefix foaf: &lt;http://xmlns.com/foaf/0.1/&gt; .
<ins class="diff-chg">
&lt;http://example.org/people#joebob&gt; a foaf:Person;
  foaf:name "Joe Bob";
</ins>
foaf:nick
(
<del class="diff-old">&quot;joe&quot;
&quot;bob&quot;
&quot;jaybee&quot;)
</del>
<ins class="diff-chg">"joe"
"bob"
"jaybee"
)
</ins>
.
</pre>
<del class="diff-old">{
  &quot;@context&quot;: {
    &quot;foaf&quot;:   &quot;http://xmlns.com/foaf/0.1/&quot;
  },
  &quot;@id&quot;:        &quot;http://example.org/people#joebob&quot;,
  &quot;@type&quot;:      &quot;foaf:Person&quot;,
  &quot;foaf:name&quot;:  &quot;Joe Bob&quot;,
  &quot;foaf:nick&quot;:  { &quot;@list&quot;: [ &quot;joe&quot;, &quot;bob&quot;, &quot;jaybe&quot; ] }
</del>
<pre class="example">{
<ins class="diff-chg">  "@context":
  {
    "foaf": "http://xmlns.com/foaf/0.1/"
  },
  "@id": "http://example.org/people#joebob",
  "@type": "foaf:Person",
  "foaf:name": "Joe Bob",
  "foaf:nick":
  {
    "@list": [ "joe", "bob", "jaybe" ]
  }
</ins>
}
</pre>
</div>
</div>
<div class="section" id="rdfa">
<h3>
<span class="secno">
A.2
</span>
RDFa
</h3>
<p>
The
following
example
describes
three
people
with
their
respective
names
and
homepages.
</p>
<del class="diff-old">&gt;
   &lt;ul&gt;
      &lt;li &gt;
        &lt;a &gt;Bob&lt;/a&gt;
      &lt;/li&gt;
      &lt;li &gt;
        &lt;a &gt;Eve&lt;/a&gt;
      &lt;/li&gt;
      &lt;li &gt;
        &lt;a &gt;Manu&lt;/a&gt;
      &lt;/li&gt;
   &lt;/ul&gt;
</del>
<pre class="example">&lt;div <span class="diff">prefix="foaf: http://xmlns.com/foaf/0.1/"</span>&gt;
<ins class="diff-chg">   &lt;ul&gt;
      &lt;li <span class="diff">typeof="foaf:Person"</span>&gt;
        &lt;a <span class="diff">rel="foaf:homepage" href="http://example.com/bob/" property="foaf:name" </span>&gt;Bob&lt;/a&gt;
      &lt;/li&gt;
      &lt;li <span class="diff">typeof="foaf:Person"</span>&gt;
        &lt;a <span class="diff">rel="foaf:homepage" href="http://example.com/eve/" property="foaf:name" </span>&gt;Eve&lt;/a&gt;
      &lt;/li&gt;
      &lt;li <span class="diff">typeof="foaf:Person"</span>&gt;
        &lt;a <span class="diff">rel="foaf:homepage" href="http://example.com/manu/" property="foaf:name" </span>&gt;Manu&lt;/a&gt;
      &lt;/li&gt;
   &lt;/ul&gt;
</ins>
&lt;/div&gt;
</pre>
<p>
An
example
JSON-LD
implementation
<ins class="diff-new">using
a
single
</ins><a href="#dfn-context" title="context" class="tref internalDFN"><ins class="diff-new">
context
</ins></a>
is
described
<del class="diff-old">below,
however,
there
are
other
ways
</del>
<ins class="diff-chg">below.
</ins></p><p class="issue"><ins class="diff-chg">
The
syntax
</ins>
to
<del class="diff-old">mark-up
this
information
such
that
the
context
</del>
<ins class="diff-chg">serialize
multiple
graphs
</ins>
is
<del class="diff-old">not
repeated.
</del>
<ins class="diff-chg">currently
being
discussed
in
</ins><a href="https://github.com/json-ld/json-ld.org/issues/68"><ins class="diff-chg">
Issue
68
</ins></a>.
</p>
<del class="diff-old">{
  &quot;@context&quot;: { &quot;foaf&quot;: &quot;http://xmlns.com/foaf/0.1/&quot; },
  &quot;@id&quot;: [
    {
      &quot;@id&quot;: &quot;_:bnode1&quot;,
      &quot;@type&quot;: &quot;foaf:Person&quot;,
      &quot;foaf:homepage&quot;: &quot;http://example.com/bob/&quot;,
      &quot;foaf:name&quot;: &quot;Bob&quot;
    },
    {
      &quot;@id&quot;: &quot;_:bnode2&quot;,
      &quot;@type&quot;: &quot;foaf:Person&quot;,
      &quot;foaf:homepage&quot;: &quot;http://example.com/eve/&quot;,
      &quot;foaf:name&quot;: &quot;Eve&quot;
    },
    {
      &quot;@id&quot;: &quot;_:bnode3&quot;,
      &quot;@type&quot;: &quot;foaf:Person&quot;,
      &quot;foaf:homepage&quot;: &quot;http://example.com/manu/&quot;,
      &quot;foaf:name&quot;: &quot;Manu&quot;
    }
  ]
</del>
<pre class="example">{
<ins class="diff-chg">  "@context":
  {
    "foaf": "http://xmlns.com/foaf/0.1/"
  },
  "@id":
  [
    {
      "@type": "foaf:Person",
      "foaf:homepage": "http://example.com/bob/",
      "foaf:name": "Bob"
    },
    {
      "@type": "foaf:Person",
      "foaf:homepage": "http://example.com/eve/",
      "foaf:name": "Eve"
    },
    {
      "@type": "foaf:Person",
      "foaf:homepage": "http://example.com/manu/",
      "foaf:name": "Manu"
    }
  ]
</ins>
}
</pre>
</div>
<div class="section" id="microformats">
<h3>
<span class="secno">
A.3
</span>
Microformats
</h3>
<p>
The
following
example
uses
a
simple
Microformats
hCard
example
to
express
how
the
Microformat
is
represented
in
JSON-LD.
</p>
<del class="diff-old">&lt;div class=&quot;vcard&quot;&gt;
 &lt;a class=&quot;url fn&quot; href=&quot;http://tantek.com/&quot;&gt;Tantek Çelik&lt;/a&gt;
</del>
<pre class="example">&lt;div class="vcard"&gt;
<ins class="diff-chg"> &lt;a class="url fn" href="http://www.markus-lanthaler.com/"&gt;Markus Lanthaler&lt;/a&gt;
</ins>
&lt;/div&gt;
</pre>
<p>
The
representation
of
the
hCard
expresses
the
Microformat
terms
in
the
<a href="#dfn-context" title="context" class="tref internalDFN">
context
</a>
and
uses
them
directly
for
the
<code>
url
</code>
and
<code>
fn
</code>
properties.
Also
note
that
the
Microformat
to
JSON-LD
processor
has
generated
the
proper
URL
type
for
<code>
http://tantek.com/
</code>.
</p>
<del class="diff-old">{
  &quot;@context&quot;:
  {
    &quot;vcard&quot;: &quot;http://microformats.org/profile/hcard#vcard&quot;,
    &quot;url&quot;: {&quot;@id&quot;: &quot;http://microformats.org/profile/hcard#url&quot;, &quot;@type&quot;: &quot;@id&quot;},
    &quot;fn&quot;: &quot;http://microformats.org/profile/hcard#fn&quot;
  },
  &quot;@id&quot;: &quot;_:bnode1&quot;,
  &quot;@type&quot;: &quot;vcard&quot;,
  &quot;url&quot;: &quot;http://tantek.com/&quot;,
  &quot;fn&quot;: &quot;Tantek Çelik&quot;
</del>
<pre class="example">{
<ins class="diff-chg">  "@context":
  {
    "vcard": "http://microformats.org/profile/hcard#vcard",
    "url":
    {
      "@id": "http://microformats.org/profile/hcard#url",
      "@type": "@id"
    },
    "fn": "http://microformats.org/profile/hcard#fn"
  },
  "@type": "vcard",
  "url": "http://www.markus-lanthaler.com/",
  "fn": "Markus Lanthaler"
</ins>
}
</pre>
</div>
<div class="section" id="microdata">
<h3>
<span class="secno">
A.4
</span>
Microdata
</h3>
<p>
The
microdata
example
below
expresses
book
information
as
a
microdata
Work
item.
</p>
<del class="diff-old">&lt;dl itemscope
    itemtype=&quot;http://purl.org/vocab/frbr/core#Work&quot;
    itemid=&quot;http://purl.oreilly.com/works/45U8QJGZSQKDH8N&quot;&gt;
 &lt;dt&gt;Title&lt;/dt&gt;
 &lt;dd&gt;&lt;cite itemprop=&quot;http://purl.org/dc/terms/title&quot;&gt;Just a Geek&lt;/cite&gt;&lt;/dd&gt;
 &lt;dt&gt;By&lt;/dt&gt;
 &lt;dd&gt;&lt;span itemprop=&quot;http://purl.org/dc/terms/creator&quot;&gt;Wil Wheaton&lt;/span&gt;&lt;/dd&gt;
 &lt;dt&gt;Format&lt;/dt&gt;
 &lt;dd itemprop=&quot;http://purl.org/vocab/frbr/core#realization&quot;
     itemscope
     itemtype=&quot;http://purl.org/vocab/frbr/core#Expression&quot;
     itemid=&quot;http://purl.oreilly.com/products/9780596007683.BOOK&quot;&gt;
  &lt;link itemprop=&quot;http://purl.org/dc/terms/type&quot; href=&quot;http://purl.oreilly.com/product-types/BOOK&quot;&gt;
  Print
 &lt;/dd&gt;
 &lt;dd itemprop=&quot;http://purl.org/vocab/frbr/core#realization&quot;
     itemscope
     itemtype=&quot;http://purl.org/vocab/frbr/core#Expression&quot;
     itemid=&quot;http://purl.oreilly.com/products/9780596802189.EBOOK&quot;&gt;
  &lt;link itemprop=&quot;http://purl.org/dc/terms/type&quot; href=&quot;http://purl.oreilly.com/product-types/EBOOK&quot;&gt;
  Ebook
 &lt;/dd&gt;
</del>
<pre class="example">&lt;dl itemscope
<ins class="diff-chg">    itemtype="http://purl.org/vocab/frbr/core#Work"
    itemid="http://purl.oreilly.com/works/45U8QJGZSQKDH8N"&gt;
 &lt;dt&gt;Title&lt;/dt&gt;
 &lt;dd&gt;&lt;cite itemprop="http://purl.org/dc/terms/title"&gt;Just a Geek&lt;/cite&gt;&lt;/dd&gt;
 &lt;dt&gt;By&lt;/dt&gt;
 &lt;dd&gt;&lt;span itemprop="http://purl.org/dc/terms/creator"&gt;Wil Wheaton&lt;/span&gt;&lt;/dd&gt;
 &lt;dt&gt;Format&lt;/dt&gt;
 &lt;dd itemprop="http://purl.org/vocab/frbr/core#realization"
     itemscope
     itemtype="http://purl.org/vocab/frbr/core#Expression"
     itemid="http://purl.oreilly.com/products/9780596007683.BOOK"&gt;
  &lt;link itemprop="http://purl.org/dc/terms/type" href="http://purl.oreilly.com/product-types/BOOK"&gt;
  Print
 &lt;/dd&gt;
 &lt;dd itemprop="http://purl.org/vocab/frbr/core#realization"
     itemscope
     itemtype="http://purl.org/vocab/frbr/core#Expression"
     itemid="http://purl.oreilly.com/products/9780596802189.EBOOK"&gt;
  &lt;link itemprop="http://purl.org/dc/terms/type" href="http://purl.oreilly.com/product-types/EBOOK"&gt;
  Ebook
 &lt;/dd&gt;
</ins>
&lt;/dl&gt;
</pre>
<p>
Note
that
the
JSON-LD
representation
of
the
Microdata
information
stays
true
to
the
desires
of
the
Microdata
community
to
avoid
contexts
and
instead
refer
to
items
by
their
full
<a href="#dfn-iri" title="iri" class="tref internalDFN">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>.
</p>
<del class="diff-old">[
  {
    &quot;@id&quot;: &quot;http://purl.oreilly.com/works/45U8QJGZSQKDH8N&quot;,
    &quot;@type&quot;: &quot;http://purl.org/vocab/frbr/core#Work&quot;,
    &quot;http://purl.org/dc/terms/title&quot;: &quot;Just a Geek&quot;,
    &quot;http://purl.org/dc/terms/creator&quot;: &quot;Whil Wheaton&quot;,
    &quot;http://purl.org/vocab/frbr/core#realization&quot;:
      [ &quot;http://purl.oreilly.com/products/9780596007683.BOOK&quot;, &quot;http://purl.oreilly.com/products/9780596802189.EBOOK&quot; ]
  },
  {
    &quot;@id&quot;: &quot;http://purl.oreilly.com/products/9780596007683.BOOK&quot;,
    &quot;@type&quot;: &quot;http://purl.org/vocab/frbr/core#Expression&quot;,
    &quot;http://purl.org/dc/terms/type&quot;: &quot;http://purl.oreilly.com/product-types/BOOK&quot;
  },
  {
    &quot;@id&quot;: &quot;http://purl.oreilly.com/products/9780596802189.EBOOK&quot;,
    &quot;@type&quot;: &quot;http://purl.org/vocab/frbr/core#Expression&quot;,
    &quot;http://purl.org/dc/terms/type&quot;: &quot;http://purl.oreilly.com/product-types/EBOOK&quot;
  }
</del>
<pre class="example">[
<ins class="diff-chg">  {
    "@id": "http://purl.oreilly.com/works/45U8QJGZSQKDH8N",
    "@type": "http://purl.org/vocab/frbr/core#Work",
    "http://purl.org/dc/terms/title": "Just a Geek",
    "http://purl.org/dc/terms/creator": "Whil Wheaton",
    "http://purl.org/vocab/frbr/core#realization":
    [
      "http://purl.oreilly.com/products/9780596007683.BOOK",
      "http://purl.oreilly.com/products/9780596802189.EBOOK"
    ]
  },
  {
    "@id": "http://purl.oreilly.com/products/9780596007683.BOOK",
    "@type": "http://purl.org/vocab/frbr/core#Expression",
    "http://purl.org/dc/terms/type": "http://purl.oreilly.com/product-types/BOOK"
  },
  {
    "@id": "http://purl.oreilly.com/products/9780596802189.EBOOK",
    "@type": "http://purl.org/vocab/frbr/core#Expression",
    "http://purl.org/dc/terms/type": "http://purl.oreilly.com/product-types/EBOOK"
  }
</ins>
]
</pre>
</div>
</div>
<div id="linked-data" class="appendix section">
<h2>
<span class="secno">
B.
</span>
Linked
Data
</h2>
<p>
The
following
definition
for
<a href="#dfn-linked_data" title="linked_data" class="tref internalDFN">
Linked
Data
</a>
is
the
one
that
will
be
used
for
this
specification.
</p>
<ol>
<li>
<dfn id="dfn-linked_data" title="linked_data">
Linked
Data
</dfn>
is
a
set
of
documents,
each
containing
a
representation
of
a
linked
data
graph.
</li>
<li>
A
<dfn id="dfn-linked_data_graph" title="linked_data_graph">
linked
data
graph
</dfn>
is
an
unordered
labeled
directed
graph,
where
nodes
are
<a href="#dfn-subject" title="subject" class="tref internalDFN">
subject
</a>
s
or
<a href="#dfn-object" title="object" class="tref internalDFN">
object
</a>
s,
and
edges
are
properties.
</li>
<li>
A
<dfn id="dfn-subject" title="subject">
subject
</dfn>
is
any
node
in
a
<a href="#dfn-linked_data_graph" title="linked_data_graph" class="tref internalDFN">
linked
data
graph
</a>
with
at
least
one
outgoing
edge.
</li>
<li>
A
<a href="#dfn-subject" title="subject" class="tref internalDFN">
subject
</a>
<em title="should" class="rfc2119">
should
</em>
be
labeled
with
an
<a href="#dfn-iri" title="iri" class="tref internalDFN">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
(an
Internationalized
Resource
Identifier
as
described
in
[
<cite>
<a href="#bib-RFC3987" rel="biblioentry" class="bibref">
RFC3987
</a>
</cite>
]).
</li>
<li>
An
<dfn id="dfn-object" title="object">
object
</dfn>
is
a
node
in
a
<a href="#dfn-linked_data_graph" title="linked_data_graph" class="tref internalDFN">
linked
data
graph
</a>
with
at
least
one
incoming
edge.
</li>
<li>
An
<a href="#dfn-object" title="object" class="tref internalDFN">
object
</a>
<em title="may" class="rfc2119">
may
</em>
be
labeled
with
an
<a href="#dfn-iri" title="iri" class="tref internalDFN">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>.
</li>
<li>
<del class="diff-old">An
object
</del>
<ins class="diff-chg">A
node
</ins><em title="may" class="rfc2119">
may
</em>
be
a
<a href="#dfn-subject" title="subject" class="tref internalDFN">
subject
</a>
and
<a href="#dfn-object" title="object" class="tref internalDFN">
object
</a>
at
the
same
time.
</li>
<li>
A
<dfn id="dfn-property" title="property">
property
</dfn>
is
an
edge
of
the
<a href="#dfn-linked_data_graph" title="linked_data_graph" class="tref internalDFN">
linked
data
graph
</a>.
</li>
<li>
A
<a href="#dfn-property" title="property" class="tref internalDFN">
property
</a>
<em title="should" class="rfc2119">
should
</em>
be
labeled
with
an
<a href="#dfn-iri" title="iri" class="tref internalDFN">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>.
</li>
<li>
An
<a href="#dfn-iri" title="iri" class="tref internalDFN">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
that
is
a
label
in
a
<a href="#dfn-linked_data_graph" title="linked_data_graph" class="tref internalDFN">
linked
data
graph
</a>
<em title="should" class="rfc2119">
should
</em>
be
dereferencable
to
a
<a href="#dfn-linked_data" title="linked_data" class="tref internalDFN">
Linked
Data
</a>
document
describing
the
labeled
<a href="#dfn-subject" title="subject" class="tref internalDFN">
subject
</a>,
<a href="#dfn-object" title="object" class="tref internalDFN">
object
</a>
or
<a href="#dfn-property" title="property" class="tref internalDFN">
property
</a>.
</li>
<li>
A
<dfn id="dfn-value" title="value">
value
</dfn>
is
an
<a href="#dfn-object" title="object" class="tref internalDFN">
object
</a>
with
a
label
that
is
not
an
<a href="#dfn-iri" title="iri" class="tref internalDFN">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
</li>
</ol>
<p>
Note
that
the
definition
for
<a href="#dfn-linked_data" title="linked_data" class="tref internalDFN">
Linked
Data
</a>
above
is
silent
on
the
topic
of
unlabeled
nodes.
Unlabeled
nodes
are
not
considered
<a href="#dfn-linked_data" title="linked_data" class="tref internalDFN">
Linked
Data
</a>.
However,
this
specification
allows
for
the
expression
of
unlabled
nodes,
as
most
graph-based
data
sets
on
the
Web
contain
a
number
of
associated
nodes
that
are
not
named
and
thus
are
not
directly
de-referenceable.
</p>
</div>
<div id="mashing-up-vocabularies" class="appendix informative section">
<h2>
<span class="secno">
C.
</span>
Mashing
Up
Vocabularies
</h2>
<p>
<em>
This
section
is
non-normative.
</em>
</p>
<p>
Developers
benefit
by
being
able
to
mash
other
<a href="#dfn-vocabulary" title="vocabulary" class="tref internalDFN">
vocabularies
</a>
into
their
JSON-LD
markup.
There
are
over
200
<a href="#dfn-vocabulary" title="vocabulary" class="tref internalDFN">
vocabularies
</a>
that
are
available
for
use
on
the
Web
today.
Some
of
these
<a href="#dfn-vocabulary" title="vocabulary" class="tref internalDFN">
vocabularies
</a>
include:
</p>
<ul>
<li>
RDF
-
for
describing
information
about
objects
and
concepts
on
the
Web.
</li>
<li>
RDFS
-
for
expressing
things
like
labels
and
comments.
</li>
<li>
XSD
-
for
specifying
basic
types
like
strings,
integers,
dates
and
times.
</li>
<li>
Dublin
Core
-
for
describing
creative
works.
</li>
<li>
FOAF
-
for
describing
social
networks.
</li>
<li>
Calendar
-
for
specifying
events.
</li>
<li>
SIOC
-
for
describing
discussions
on
blogs
and
websites.
</li>
<li>
CCrel
-
for
describing
Creative
Commons
and
other
types
of
licenses.
</li>
<li>
GEO
-
for
describing
geographic
location.
</li>
<li>
VCard
-
for
describing
organizations
and
people.
</li>
<li>
DOAP
-
for
describing
projects.
</li>
</ul>
<p>
You
can
use
these
<a href="#dfn-vocabulary" title="vocabulary" class="tref internalDFN">
vocabularies
</a>
in
combination,
like
so:
</p>
<del class="diff-old">{
  &quot;@context&quot;:
  {
    &quot;foaf&quot;: &quot;http://xmlns.com/foaf/0.1/&quot;,
    &quot;sioc&quot;: &quot;http://rdfs.org/sioc/ns#&quot;,
    &quot;rdfs&quot;: &quot;http://www.w3.org/2000/01/rdf-schema#&quot;
  },
  &quot;@type&quot;: &quot;foaf:Person&quot;,
  &quot;foaf:name&quot;: &quot;Manu Sporny&quot;,
  &quot;foaf:homepage&quot;: &quot;http://manu.sporny.org/&quot;,
  &quot;sioc:avatar&quot;: &quot;http://twitter.com/account/profile_image/manusporny&quot;,
  &quot;rdfs:comment&quot;: &quot;Likes puppies, unicorns and rainbows.&quot;
</del>
<pre class="example">{
<ins class="diff-chg">  "@context":
  {
    "foaf": "http://xmlns.com/foaf/0.1/",<span class="diff">
    "sioc": "http://rdfs.org/sioc/ns#",
    "rdfs": "http://www.w3.org/2000/01/rdf-schema#"</span>
  },
  "@type": "foaf:Person",
  "foaf:name": "Manu Sporny",
  "foaf:homepage": "http://manu.sporny.org/",<span class="diff">
  "sioc:avatar": "http://twitter.com/account/profile_image/manusporny",
  "rdfs:comment": "Likes puppies, unicorns and rainbows."</span>
</ins>
}
</pre>
<p>
Developers
can
also
specify
their
own
<a href="#dfn-vocabulary" title="vocabulary" class="tref internalDFN">
vocabulary
</a>
documents
by
modifying
the
<a href="#dfn-active_context" title="active_context" class="tref internalDFN">
active
context
</a>
in-line
using
the
<code>
@context
</code>
keyword,
like
so:
</p>
<del class="diff-old">{
  &quot;@context&quot;:
  {
    &quot;foaf&quot;: &quot;http://xmlns.com/foaf/0.1/&quot;,
    &quot;sioc&quot;: &quot;http://rdfs.org/sioc/ns#&quot;,
    &quot;rdfs&quot;: &quot;http://www.w3.org/2000/01/rdf-schema#&quot;,

  },
  &quot;@type&quot;: &quot;foaf:Person&quot;,
  &quot;foaf:name&quot;: &quot;Manu Sporny&quot;,
  &quot;foaf:homepage&quot;: &quot;http://manu.sporny.org/&quot;,
  &quot;sioc:avatar&quot;: &quot;http://twitter.com/account/profile_image/manusporny&quot;,
  &quot;rdfs:comment&quot;: &quot;Likes puppies, unicorns and rainbows.&quot;

</del>
<pre class="example">{
<ins class="diff-chg">  "@context":
  {
    "foaf": "http://xmlns.com/foaf/0.1/",
    "sioc": "http://rdfs.org/sioc/ns#",
    "rdfs": "http://www.w3.org/2000/01/rdf-schema#",
</ins>    <span class="diff">"myvocab": "http://example.org/myvocab#"</span>
<ins class="diff-chg">
  },
  "@type": "foaf:Person",
  "foaf:name": "Manu Sporny",
  "foaf:homepage": "http://manu.sporny.org/",
  "sioc:avatar": "http://twitter.com/account/profile_image/manusporny",
  "rdfs:comment": "Likes puppies, unicorns and rainbows."
</ins>  <span class="diff">"myvocab:personality": "friendly"</span>
}
</pre>
</div>
<div id="iana-considerations" class="appendix informative section">
<h2>
<span class="secno">
D.
</span>
IANA
Considerations
</h2>
<p>
<em>
This
section
is
non-normative.
</em>
</p>
<p>
This
section
is
included
merely
for
standards
community
review
and
will
be
submitted
to
the
Internet
Engineering
Steering
Group
if
this
specification
becomes
a
W3C
Recommendation.
</p>
<dl>
<dt>
Type
name:
</dt>
<dd>
application
</dd>
<dt>
Subtype
name:
</dt>
<dd>
ld+json
</dd>
<dt>
Required
parameters:
</dt>
<dd>
None
</dd>
<dt>
Optional
parameters:
</dt>
<dd>
<dl>
<dt>
<code>
form
</code>
</dt>
<dd>
Determines
the
serialization
form
for
the
JSON-LD
document.
Valid
values
<del class="diff-old">include;
compacted
,
</del>
<ins class="diff-chg">are
</ins>
<code>
expanded
<del class="diff-old">,
</del>
</code>
and
<code>
normalized
</code>.
If
no
form
is
specified
in
an
HTTP
request
header
to
an
HTTP
server,
the
server
<em title="may" class="rfc2119">
may
</em>
choose
any
form.
If
no
form
is
specified
for
an
HTTP
client,
the
form
<em title="must not" class="rfc2119">
must
not
</em>
be
assumed
to
take
any
particular
form.
</dd>
</dl>
</dd>
<dt>
Encoding
considerations:
</dt>
<dd>
The
same
as
the
<code>
application/json
</code>
MIME
media
type.
</dd>
<dt>
Security
considerations:
</dt>
<dd>
Since
JSON-LD
is
intended
to
be
a
pure
data
exchange
format
for
directed
graphs,
the
serialization
<em title="should not" class="rfc2119">
should
not
</em>
be
passed
through
a
code
execution
mechanism
such
as
JavaScript's
<code>
eval()
</code>
function.
It
is
<em title="recommended" class="rfc2119">
recommended
</em>
that
a
conforming
parser
does
not
attempt
to
directly
evaluate
the
JSON-LD
serialization
and
instead
purely
parse
the
input
into
a
language-native
data
structure.
</dd>
<dt>
Interoperability
considerations:
</dt>
<dd>
Not
Applicable
</dd>
<dt>
Published
specification:
</dt>
<dd>
The
<a href="http://json-ld.org/spec/latest/">
JSON-LD
</a>
specification.
</dd>
<dt>
Applications
that
use
this
media
type:
</dt>
<dd>
Any
programming
environment
that
requires
the
exchange
of
directed
graphs.
Implementations
of
JSON-LD
have
been
created
for
JavaScript,
Python,
Ruby,
PHP
and
C++.
</dd>
<dt>
Additional
information:
</dt>
<dd>
<dl>
<dt>
Magic
number(s):
</dt>
<dd>
Not
Applicable
</dd>
<dt>
File
extension(s):
</dt>
<dd>.jsonld
</dd>
<dt>
Macintosh
file
type
code(s):
</dt>
<dd>
TEXT
</dd>
</dl>
</dd>
<dt>
Person
&amp;
email
address
to
contact
for
further
information:
</dt>
<dd>
Manu
Sporny
&lt;msporny@digitalbazaar.com&gt;
</dd>
<dt>
Intended
usage:
</dt>
<dd>
Common
</dd>
<dt>
Restrictions
on
usage:
</dt>
<dd>
None
</dd>
<dt>
Author(s):
</dt>
<dd>
Manu
Sporny,
Gregg
Kellogg,
<ins class="diff-new">Markus
Lanthaler,
</ins>
Dave
Longley
</dd>
<dt>
Change
controller:
</dt>
<dd>
W3C
</dd>
</dl>
</div>
<div id="acknowledgements" class="appendix informative section">
<h2>
<span class="secno">
E.
</span>
Acknowledgements
</h2>
<p>
<em>
This
section
is
non-normative.
</em>
</p>
<p>
The
editors
would
like
to
thank
Mark
Birbeck,
who
provided
a
great
deal
of
the
initial
push
behind
the
JSON-LD
work
via
his
work
on
RDFj,
Dave
Longley,
Dave
Lehn
and
Mike
Johnson
who
reviewed,
provided
feedback,
and
performed
several
implementations
of
the
specification,
and
Ian
Davis,
who
created
RDF/JSON.
Thanks
also
to
Nathan
Rixham,
Bradley
P.
Allen,
Kingsley
Idehen,
Glenn
McDonald,
Alexandre
Passant,
Danny
Ayers,
Ted
Thibodeau
Jr.,
Olivier
Grisel,
Niklas
Lindström,
Markus
Lanthaler,
and
Richard
Cyganiak
for
their
input
on
the
specification.
</p>
</div>
<div class="appendix section" id="references">
<h2>
<span class="secno">
F.
</span>
References
</h2>
<div class="section" id="normative-references">
<h3>
<span class="secno">
F.1
</span>
Normative
references
</h3>
<dl class="bibliography">
<dt id="bib-BCP47">
[BCP47]
</dt>
<dd>
A.
Phillips,
M.
Davis.
<a href="http://tools.ietf.org/rfc/bcp/bcp47.txt">
<cite>
Tags
for
Identifying
Languages
</cite>
</a>
September
2009.
IETF
Best
Current
Practice.
URL:
<a href="http://tools.ietf.org/rfc/bcp/bcp47.txt">
http://tools.ietf.org/rfc/bcp/bcp47.txt
</a>
</dd>
<dt id="bib-RFC3987">
[RFC3987]
</dt>
<dd>
M.
Dürst;
M.
Suignard.
<a href="http://www.ietf.org/rfc/rfc3987.txt">
<cite>
Internationalized
Resource
Identifiers
(IRIs).
</cite>
</a>
January
2005.
Internet
RFC
3987.
URL:
<a href="http://www.ietf.org/rfc/rfc3987.txt">
http://www.ietf.org/rfc/rfc3987.txt
</a>
</dd>
<dt id="bib-RFC4627">
[RFC4627]
</dt>
<dd>
D.
Crockford.
<a href="http://www.ietf.org/rfc/rfc4627.txt">
<cite>
The
application/json
Media
Type
for
JavaScript
Object
Notation
(JSON)
</cite>
</a>
July
2006.
Internet
RFC
4627.
URL:
<a href="http://www.ietf.org/rfc/rfc4627.txt">
http://www.ietf.org/rfc/rfc4627.txt
</a>
</dd>
<dt id="bib-RFC5988">
<ins class="diff-new">[RFC5988]
</ins></dt><dd><ins class="diff-new">
M.
Nottingham.
</ins><a href="http://tools.ietf.org/rfc/rfc5988"><cite><ins class="diff-new">
Web
Linking
</ins></cite></a><ins class="diff-new">
October
2010.
IETF
Standard.
URL:
</ins><a href="http://tools.ietf.org/rfc/rfc5988.txt"><ins class="diff-new">
http://tools.ietf.org/rfc/rfc5988.txt
</ins></a></dd>
<dt id="bib-WEBIDL">
[WEBIDL]
</dt>
<dd>
Cameron
McCormack.
<a href="http://www.w3.org/TR/2011/WD-WebIDL-20110927/">
<cite>
Web
IDL.
</cite>
</a>
27
September
2011.
W3C
Working
Draft.
(Work
in
progress.)
URL:
<a href="http://www.w3.org/TR/2011/WD-WebIDL-20110927/">
http://www.w3.org/TR/2011/WD-WebIDL-20110927/
</a>
</dd>
</dl>
</div>
<div class="section" id="informative-references">
<h3>
<span class="secno">
F.2
</span>
Informative
references
</h3>
<dl class="bibliography">
<dt id="bib-ECMA-262">
[ECMA-262]
</dt>
<dd>
<a href="http://www.ecma-international.org/publications/standards/Ecma-262.htm">
<cite>
ECMAScript
Language
Specification.
</cite>
</a>
December
1999.
URL:
<a href="http://www.ecma-international.org/publications/standards/Ecma-262.htm">
http://www.ecma-international.org/publications/standards/Ecma-262.htm
</a>
</dd>
<dt id="bib-HTML-RDFA">
[HTML-RDFA]
</dt>
<dd>
Manu
Sporny;
et
al.
<a href="http://www.w3.org/TR/rdfa-in-html/">
<cite>
HTML+RDFa
</cite>
</a>
04
March
2010.
W3C
Working
Draft.
URL:
<a href="http://www.w3.org/TR/rdfa-in-html/">
http://www.w3.org/TR/rdfa-in-html/
</a>
</dd>
<dt id="bib-JSON-LD-API">
[JSON-LD-API]
</dt>
<dd>
Manu
Sporny,
Gregg
Kellogg,
Dave
Longley,
Eds.
<cite>
<a href="http://json-ld.org/spec/latest/json-ld-api/">
JSON-LD
API
</a>
</cite>
Latest.
W3C
Editor's
Draft.
URL:
<a href="http://json-ld.org/spec/latest/json-ld-api/">
http://json-ld.org/spec/latest/json-ld-api/
</a>
</dd>
<dt id="bib-RDF-PRIMER">
[RDF-PRIMER]
</dt>
<dd>
Frank
Manola;
Eric
Miller.
<a href="http://www.w3.org/TR/2004/REC-rdf-primer-20040210/">
<cite>
RDF
Primer.
</cite>
</a>
10
February
2004.
W3C
Recommendation.
URL:
<a href="http://www.w3.org/TR/2004/REC-rdf-primer-20040210/">
http://www.w3.org/TR/2004/REC-rdf-primer-20040210/
</a>
</dd>
<dt id="bib-RDFA-CORE">
[RDFA-CORE]
</dt>
<dd>
Shane
McCarron;
et
al.
<a href="http://www.w3.org/TR/2011/WD-rdfa-core-20111215">
<cite>
RDFa
Core
1.1:
Syntax
and
processing
rules
for
embedding
RDF
through
attributes.
</cite>
</a>
15
December
2011.
W3C
Working
Draft.
URL:
<a href="http://www.w3.org/TR/2011/WD-rdfa-core-20111215">
http://www.w3.org/TR/2011/WD-rdfa-core-20111215
</a>
</dd>
<dt id="bib-TURTLE">
[TURTLE]
</dt>
<dd>
David
Beckett,
Tim
Berners-Lee.
<a href="http://www.w3.org/TeamSubmission/turtle/">
<cite>
Turtle:
Terse
RDF
Triple
Language.
</cite>
</a>
January
2008.
W3C
Team
Submission.
URL:
<a href="http://www.w3.org/TeamSubmission/turtle/">
http://www.w3.org/TeamSubmission/turtle/
</a>
</dd>
<dt id="bib-XML-NAMES">
[XML-NAMES]
</dt>
<dd>
Richard
Tobin;
et
al.
<a href="http://www.w3.org/TR/2009/REC-xml-names-20091208/">
<cite>
Namespaces
in
XML
1.0
(Third
Edition).
</cite>
</a>
8
December
2009.
W3C
Recommendation.
URL:
<a href="http://www.w3.org/TR/2009/REC-xml-names-20091208/">
http://www.w3.org/TR/2009/REC-xml-names-20091208/
</a>
</dd>
</dl>
</div>
</div>
</body>
</html>
